United States v. Yu

United States Court of Appeals For the First Circuit

Nos. 23-1585 24-1325

UNITED STATES,

Appellee,

v.

HAOYANG YU,

Defendant, Appellant.

APPEALS FROM THE UNITED STATES DISTRICT COURT FOR THE DISTRICT OF MASSACHUSETTS

[Hon. William G. Young, U.S. District Judge]

Before

Montecalvo, Lipez, and Aframe, Circuit Judges.

William W. Fick, with whom Daniel N. Marx, Amy Barsky, and Fick & Marx LLP were on brief, for appellant.

Karen Lisa Eisenstadt, Assistant United States Attorney, with whom Leah B. Foley, United States Attorney, was on brief, for appellee.

December 11, 2025  MONTECALVO, Circuit Judge. Haoyang Yu worked for Analog

Devices, Inc. ("ADI"), a company that designs and produces

microchips. While employed there, Yu downloaded ADI's proprietary

information and held onto it after leaving the company. He soon

started selling microchips that were similar to ADI's. A grand

jury indicted Yu on twenty-one counts, spanning possession of

stolen trade secrets, wire fraud, illegal exports of controlled

technology to Taiwan, visa fraud, and unlawful procurement of

citizenship. At trial, a jury convicted Yu on just the first

count: unlawful possession of a trade secret in violation of

18 U.S.C. § 1832(a)(3). Yu now appeals, challenging the

sufficiency of the evidence as to particular elements of the

charge. He also claims unconstitutional selective enforcement and

prosecution, alleging that, because he is from China, he was

investigated and prosecuted much more harshly than someone who is

not ethnically Chinese would have been.

For the following reasons, we affirm.

I. Factual Background

We recount the facts relevant to Yu's sufficiency

challenge in the light most favorable to the prosecution. See

United States v. Díaz-Rosado, 857 F.3d 116, 117 (1st Cir. 2017).

We provide a neutral summary of the facts relevant to his other

claims. See id.

- 2 -  Because the jury ultimately convicted Yu on only one

count -- possession of a stolen trade secret, specifically, "[t]he

design layout and GDS file for the HMC1022A microchip" -- we focus

on the facts relevant to that charge.1 We refer to this electronic

file that Yu was accused of possessing as the "charged file."

We begin with relevant background about ADI and its work.

ADI creates microchips, which are devices that process and store

information and help make electronic appliances work. As relevant

to this case, ADI develops radio frequency and microwave amplifier

microchips (also called "monolithic microwave integrated circuits"

or "MMICs") that allow electronic devices to broadcast and send

signals over the air. MMICs are tiny; comparing them to the tip

of a pencil, they can measure approximately one pencil tip long

and two pencil tips wide. ADI designs MMICs for use in

infrastructure -- for example, airplanes and cell phone

towers -- as opposed to consumer goods. ADI has customers in the

cell phone, auto, aerospace, and defense industries. ADI's MMICs

have military uses, such as in satellites and radar. ADI designs

the microchips and uses Win Semiconductor ("Win"), a company based

in Taiwan, to manufacture them.

In 2014, ADI acquired another microchip company called

Hittite Microwave Corporation ("Hittite"). Before the

1A GDS file is the type of computer file used to convey a design layout.

- 3 - acquisition, Hittite manufactured some of its MMIC designs at Win

and some with another manufacturer. Each microchip manufacturer

has its own particular set of manufacturing technologies, which

makes it difficult for designers to switch manufacturers. But

after the acquisition, ADI began the painstaking process of

translating Hittite's non-Win designs into designs that could be

manufactured by Win.

Designing a MMIC is an iterative process. First, the

designer creates a three-dimensional "schematic" for how the MMIC

should operate, involving potentially thousands of mathematical

formulas to model how various components work together. This

process can take an experienced designer several weeks. Next, the

designer uses a computer to run simulations to test how well the

schematic works. The designer runs thousands of simulations to

refine the schematic.

At the next stage, the designer creates the layout, which

is a diagram that describes precisely how the components of the

MMIC fit together and contains all the information needed to

manufacture the MMIC. The designer then returns to the schematic

and simulation stages and refines the design layout. The overall

process, from starting the first schematic to creating a design

layout ready to be manufactured and tested, can take three to six

months.

- 4 -  When the designer thinks the design layout is ready, ADI

creates what is called a GDS file and sends it to Win to manufacture

a prototype. Manufacturing a MMIC prototype typically takes Win

around six weeks and costs ADI $35,000 to $50,000. Win

manufactures thousands of the prototype MMIC, which ADI then tests

hundreds of times on equipment that costs hundreds of thousands of

dollars. The first prototype is almost never ready for the market.

Instead, the designer will return to the design phase to further

refine the design, creating new prototypes as needed until the

design layout is finalized and the MMIC is ready to go to market.

A typical MMIC sells for around $200.

The translation process, which ADI used to recreate

Hittite's existing MMICs into design layouts that Win could

manufacture, involves the same iterative design process. But

translations can take even more time and effort because the

finished product must exactly mirror the existing product. In

other words, the translation should not be better or worse; it

must be the same in every way. To track these translated MMICs,

ADI named the finished product using "HMC" (to denote Hittite),

followed by Hittite's identification number for the original MMIC,

and appended an "A" to it to denote that it was ADI's translation

rather than the original.

Yu had recently begun working at Hittite at the time of

its acquisition in 2014. He became an ADI employee in the

- 5 - acquisition. Yu had previously worked on microchip products geared

towards consumer applications, but at ADI, he transitioned to

microchips for industrial use and learned the relevant skillset to

work on translating Hittite's MMIC designs.

Yu signed confidentiality agreements with ADI, which

defined "[c]onfidential [i]nformation" as including "all

information acquired by [Yu] from ADI . . . that relates to the

past, present[,] or potential . . . products . . . of ADI." Yu

agreed that he would not disclose this confidential information to

any third parties, would not "make use" of such information "for

[his] own purposes . . . under any circumstances during or after

the term of [his] employment," and that he would return all such

information to ADI at the end of his employment.

In approximately mid-2016, Yu began saving copies of

some of ADI's GDS files to his personal computer. He changed the

names of some of these files to the names of Pokémon characters.

ADI's file called "K8600_TOP.gds" contained multiple MMIC design

layouts, including the HMC1022A prototype (the charged file). When

Yu copied this file, he renamed it as "Kids8600.jpg" as though it

were a photograph of his children. However, one could only open

the file by changing the file extension from ".jpg" to ".gds."

In January 2017, Yu emailed Win to ask whether it would

work with a small business. Win replied that it would, but that

it would likely require payment upfront and that it would need a

- 6 - non-disclosure agreement. Yu agreed to these terms. Yu also began

reaching out to potential customers about working with a new MMIC

design company.

In March 2017, Yu registered a new company called Tricon

MMIC, LLC ("Tricon") under his wife's name, Yanzhi Chen. Tricon's

website advertised its MMICs as potential substitutes for or

improved versions of ADI's MMICs, including the HMC1022.

On June 1, 2017, Yu sent his first design layout GDS

file to Win to manufacture. He requested that Win "[p]lease treat

[the file] as proprietary data." Typically, it takes designers

"several weeks to several months" after receiving Win's "process

design kit" to refine and finalize their designs, yet Yu sent his

first GDS file to Win just two days after receiving its kit. Also

in June of 2017, Yu wrote to a business contact to ask for help

promoting a new company that he was starting. But Yu asked his

contact to "keep [the new company] a secret for now" because he

did not "want to be noticed by [ADI]."

Yu received the first set of manufactured MMICs from Win

in mid-July 2017. Win representatives noted that the Tricon MMICs

did not appear to be products of the typical iterative process

where designers refine the design for a particular MMIC over time.

Rather, the Tricon MMICs appeared to be "finished good[s]" from

the first production.

- 7 -  On July 31, 2017, Yu resigned from ADI. After he left

the company, he retained the ADI information, including MMIC design

files, that he had copied to his personal computer. At the

beginning of August, Yu began shipping samples and orders of Tricon

MMICs to customers.

In July 2018, Yu sent Win another GDS file containing

additional design layouts, including two named TM5051 and TM5052.

The Tricon website advertised the TM5051 and TM5052 as the

equivalent of the "ADI (Hittite)" "HMC1022 with more bandwidth."

Yu received the manufactured TM5051 and TM5052 MMICs in early

September 2018.

ADI released its HMC1022A microchip for sale on

February 15, 2019.

II. Procedural History

A grand jury returned an indictment against Yu and Tricon

on June 11, 2019. The fifteen counts against Yu spanned theft of

a trade secret, copying a trade secret, possession of a trade

secret, and smuggling.

Three days later, on June 14, 2019, federal agents

searched Yu's house pursuant to a warrant. The agents also

arrested him, although he was released on bond five days later.

A. Pretrial Motions and Superseding Indictments

On June 22, 2020, Yu moved to dismiss the indictment due

to selective enforcement and prosecution in violation of his equal

- 8 - protection rights under the Fifth Amendment. He argued that law

enforcement had targeted him for investigation (the basis for his

selective enforcement claim) and that government prosecutors had

targeted him for prosecution (the basis for his selective

prosecution claim) based on his Chinese ethnicity. In support, he

pointed to examples of non-Chinese people who had stolen trade

secrets from U.S. companies, including ADI, but faced only civil

claims for their actions. He also alleged that statistics showed

that federal prosecutors targeted people of Chinese descent in

espionage cases. In October, the district court decided to keep

the motion under advisement pending trial because, in the district

court's words, "trials have a way of testing the evidence."

On October 1, 2020, the grand jury returned a first

superseding indictment. Yu was charged with additional counts

covering wire fraud, transportation of stolen goods, visa fraud,

and unlawful procurement of citizenship. The indictment also added

Yu's wife, Yanzhi Chen, as a defendant on the three wire fraud

counts.

A year later, the grand jury returned a second

superseding indictment that was largely similar but added two

counts for illegal exports of controlled technology to Taiwan.

A third (and final) superseding indictment, filed on

January 26, 2022, and charging twenty-one counts, was similar to

the second superseding indictment but dropped the original counts

- 9 - for theft of trade secrets. As relevant here, it listed the

specific computer files that underlay each count for possession or

attempted possession of stolen trade secrets, in violation of

18 U.S.C. § 1832(a)(3), (4). Count One specified Yu's alleged

possession of "[t]he design layout and GDS file for the HMC1022A

microchip."

On March 28, 2022, on Yu's motion, the district court

dismissed one wire fraud count before trial as time-barred.

B. Trial

On May 3, 2022, the case against Yu and Tricon proceeded

to a jury trial.2 Yu faced twenty-one counts: twelve counts of

possession and attempted possession of stolen trade secrets; five

counts of wire fraud; two counts of illegal exports of controlled

technology to Taiwan; one count of visa fraud; and one count of

unlawful procurement of citizenship. The trial lasted fifteen

days.

At the close of the prosecution's case, Yu and Tricon

moved for judgments of acquittal due to insufficient evidence.

The district court took the motion under advisement. After

presenting evidence, the defense renewed this motion. The district

court granted acquittal as to the count charging Yu with unlawful

2 In July 2021, the district court had held that Yu and Tricon would be tried separately from Chen.

- 10 - procurement of citizenship but allowed the remaining counts to go

to the jury.

The jury returned a guilty verdict on Count One,

convicting Yu of possessing a stolen trade secret for the design

layout and GDS file for the HMC1022A microchip. The jury acquitted

Yu on all other counts and acquitted Tricon on all counts that it

faced.3

C. Post-Trial Motions

Several weeks after the jury verdict, on June 13, 2022,

the district court entered an order regarding Yu's motion to

dismiss. The district court denied the motion to dismiss due to

unconstitutional selective prosecution.4 It held that Yu had not

presented "sufficiently clear evidence that 'similarly situated

individuals of a different race were not prosecuted,'" as required

by United States v. Armstrong, 517 U.S. 456, 464-65 (1996).

However, the district court reasoned that selective enforcement

claims do not have as high an evidentiary burden as selective

prosecution claims. Therefore, the district court allowed Yu

"limited discovery" regarding the selective enforcement claim and

continued to reserve its decision.

3 A month later, on June 28, 2022, the prosecution filed a motion to dismiss the charges against Chen. The district court granted the motion on July 14, 2022. 4 The district court later denied Yu's motion to reconsider the denial of his selective prosecution claim.

- 11 -  Following discovery, at a hearing on May 11, 2023, the

district court denied Yu's motion to dismiss based on selective

enforcement. The district court expressed concern about "implicit

bias" and anti-Asian racism. However, it concluded by a

preponderance of the evidence that law enforcement likely would

have investigated Yu for the specific conduct at issue in this

case even had he not been from China or of Chinese descent.

D. Sentencing

On June 1, 2023, the district court sentenced Yu to six

months' imprisonment and thirty-six months of supervised release

and ordered payment of a $55,000 fine. The district court later

ordered restitution in the amount of nearly $200,000 based on the

legal fees that ADI had incurred. Yu has completed the prison

sentence and satisfied the restitution order.

III. Discussion

We begin with Yu's various arguments that the evidence

was insufficient to support his conviction before turning to his

arguments that he was selectively investigated and prosecuted

based on his ethnicity, in violation of the Fifth Amendment.

A. Sufficiency of the Evidence

Yu brings four distinct arguments as to why the evidence

against him was insufficient. We address each in turn.

- 12 -  1. Standard of Review

We review the sufficiency of the evidence de novo,

examining the evidence "in the light most favorable to the

prosecution and decid[ing] whether that evidence, including all

plausible inferences drawn therefrom, would allow a rational

factfinder to conclude beyond a reasonable doubt that the defendant

committed the charged count or crime." Díaz-Rosado, 857 F.3d at

120 (citations omitted).

2. The Charged File

Yu first argues that the evidence against him was

insufficient to support Count One, which charged him with

unlawfully possessing "[t]he design layout and GDS for the HMC1022A

microchip." (Emphases added.) Yu contends that this description

refers to ADI's final HMC1022A design, as it was released for sale

in February 2019. But, Yu argues, he never possessed that final

HMC1022A design. Instead, Yu continues, he possessed "an earlier,

abandoned 'prototype'" that was not specified in the indictment,

and the evidence at trial related to his possession of that earlier

prototype. In Yu's view, "[b]roadening the indictment . . . in an

attempt to encompass the trial evidence about an abandoned

prototype design for what eventually became the HMC1022A would be

an impermissible constructive amendment." See United States v.

Brandao, 539 F.3d 44, 57 (1st Cir. 2008) ("A constructive amendment

occurs when the charging terms of an indictment are altered, either

- 13 - literally or in effect, by prosecution or court after the grand

jury has last passed upon them." (quoting United States v. Pierre,

484 F.3d 75, 81 (1st Cir. 2007))).

In response, the government argues that the indictment

employed "the" in a colloquial sense and that Yu is improperly

reading the indictment as if it were a statute. The government

contends that it is obvious both as a matter of common sense and

in the context of the indictment that Yu was charged with

possessing a prototype, not the final HMC1022A design. First, Yu

could not have possessed the final HMC1022A design before it

existed. Second, the full indictment made clear that Yu was

charged with possessing the specific files that he had downloaded

from ADI's servers, which he then used to create microchips based

on ADI's designs.

Finally, the government disagrees with Yu's

characterization of any discrepancy between the indictment and the

evidence at trial as a constructive amendment. Instead, the

government says, the claim should be properly described as a

variance, meaning that "the government relie[d] at trial on

different facts than those alleged in the indictment to prove the

same offense." (Quoting United States v. Katana, 93 F.4th 521,

530 (1st Cir. 2024).) But, the government continues, Yu waived

any claim of variance by failing to advance the argument in his

- 14 - briefing on appeal, even though he had argued before the district

court that there had been a variance.

We need not delve into whether the proper claim would be

one for constructive amendment or variance, because we agree with

the government that the indictment, read in its entirety, clearly

specifies the file with which Yu was charged with possessing. See

Katana, 93 F.4th at 530 (reviewing preserved claims of constructive

amendment and variance by "read[ing] the indictment '"in a plain

and commonsense manner," focusing on the text and what it reveals

about the scope of the crimes the grand jury intended to charge'"

(quoting United States v. Martínez, 994 F.3d 1, 13 (1st Cir.

2021))).

The indictment begins with over ten pages of "General

Allegations," which give context to the charges enumerated later.

Specifically, the indictment alleges that, starting no later than

September 2016 and "continu[ing] for several months," Yu began

"stealing ADI's confidential information by downloading files from

ADI's servers" and saving them on his personal computers and

personal Google Drive account. The indictment further alleges

that, in July 2018, Yu sent Win a GDS file that "contained

manufacturing data for about 13 microchips based on stolen ADI

designs," including the TM5051 and TM5052. The indictment also

includes an image from the Tricon website, which described the

TM5051 and TM5052 as similar to ADI's "HMC1022 with more

- 15 - bandwidth." Finally, the indictment alleges that, when Yu's home

was ultimately searched in June 2019, Yu had in his possession

over 2,000 files that were ADI property; "these files

matched -- bit-for-bit -- those developed, owned, and still

maintained by ADI."

After this full description, the indictment lists the

first twelve counts of possession and attempted possession of

stolen trade secrets. The indictment specifies the files referred

to in each count. Count One is based on Yu's alleged possession

of "[t]he design layout and GDS file for the HMC1022A microchip,"

which Yu possessed on approximately June 14, 2019, the date that

federal agents searched his home.

Reading the indictment "in a plain and commonsense

manner," see id., the description in Count One clearly refers to

ADI's prototype for what ultimately became the HMC1022A, not to

ADI's finished version of the HMC1022A that eventually went to

market. The indictment clarifies that it refers to the file that

Yu downloaded from the ADI servers and used to create his own

MMICs, which his company's website advertised as being a

replacement for the HMC1022. In context, the indictment makes

clear which file Yu was charged with possessing.

We therefore disagree with Yu's assertion that "there

was no evidence that Mr. Yu ever possessed the alleged 'trade

secret' charged in Count One." On the contrary, as Yu concedes,

- 16 - the evidence showed "that he possessed . . . a design layout and

GDS file for an earlier . . . 'prototype,' which ADI created

during its 'translation' process from the legacy HMC1022 into what

eventually . . . became the final HMC1022A." Because the

indictment charged Yu with possessing that earlier prototype, his

first sufficiency challenge fails.

3. Independent Economic Value on the Charged Date of Possession

Next, Yu disputes that the file in his possession

constituted a trade secret on the charged date. He points to the

definition of a "trade secret," which requires, in part, that "the

information derives independent economic value, actual or

potential, from not being generally known to, and not being readily

ascertainable through proper means by, another person who can

obtain economic value from the disclosure or use of the

information." 18 U.S.C. § 1839(3)(B).

Yu notes that the indictment specified that he possessed

a trade secret on approximately June 14, 2019, but he argues that

the design could not have constituted a trade secret at that time.

This is so, he contends, because ADI had released HMC1022A to the

public in February 2019, meaning that its features were "readily

ascertainable" and did not constitute a trade secret by June 2019.

See BondPro Corp. v. Siemens Power Generation, Inc., 463 F.3d 702,

706 (7th Cir. 2006) ("A trade secret that becomes public knowledge

is no longer a trade secret."). Yu's argument leans heavily on

- 17 - casting MMIC design layouts as relatively easy to reverse-engineer

from the finished MMIC. Therefore, according to Yu, the evidence

was insufficient that he possessed a trade secret on or around the

charged date.

In response, the government strongly contests the notion

that the final design was "readily ascertainable" from the

microchip and therefore (as Yu argues) no longer a trade secret.

The government points to extensive evidence about the time,

expense, labor, and difficulty involved in trying to

reverse-engineer a MMIC design layout from a physical microchip.

Finally, the government argues that Yu could not have

reverse-engineered his microchip from ADI's final design because

ADI's final design was different from the earlier prototype that

Yu had taken with him.

In essence, Yu asks us to disregard the prosecution's

evidence that reverse engineering a design from a physical

microchip is both labor- and time-intensive and instead adopt his

characterization of the process as relatively easy and quick. This

we cannot do. Viewing the evidence in the light most favorable to

the prosecution, there was sufficient evidence for a rational juror

to conclude that the charged file was still a trade secret on the

approximate date named in the indictment. See Díaz-Rosado, 857

F.3d at 120. The prosecution presented evidence that the

competitive advantage of a MMIC design comes from the exact size,

- 18 - placement, and relationship of a microchip's many components. When

attempting to reverse-engineer a design, although a microscope may

assist in viewing these components, even with magnification, the

lower layers of a MMIC are still difficult to discern. The

prosecution presented evidence to counter Yu's suggestion that

"counting pixels" using a powerful microscope to determine the

placement and proportions of MMIC components is straightforward.

Reverse-engineering from magnified images can take "several weeks

to a month" of dedicated work to prepare the schematic and layout,

plus more time for testing and tapeouts. And the entire process

requires expensive tools and software. The prosecution's evidence

showed, then, that while reverse-engineering a MMIC design from a

physical chip is possible, it requires significant cost, time, and

skill -- the design is not "readily ascertainable." From this

evidence, a rational juror could easily have concluded that the

files that Yu took still constituted a trade secret on

approximately June 14, 2019, even though the HMC1022A was publicly

available at that time.

4. Independent Economic Value at Any Time

Yu next argues that the evidence was insufficient to

show that the files he took constituted a trade secret at any point

in time. He characterizes the ADI files in his possession as "the

abandoned HMC1022A prototype" that was "merely an early attempt to

'translate' a legacy design that had been on the market for years

- 19 - and that closely resembled other competitor chips." Because

Hittite's legacy HMC1022 had been on the market and therefore its

features were "readily ascertainable," Yu argues, ADI's early

attempt to translate it by way of the prototype design (the charged

file) was not a trade secret. It could not be a trade secret, he

argues, because the file did not derive independent economic value

from secrecy.

The government responds by again rejecting the notion

that the design layout for the legacy HMC1022 was "readily

ascertainable," characterizing Yu's argument as "a rehash of his

failed reverse-engineering argument [regarding the HMC1022A]."

The government argues that Yu's prototype design was a "'short

cut' to creating a competitive chip," demonstrating its economic

value. Indeed, the government argues that the reason a company

like ADI invests so many resources into the translation process is

that the ultimate product is profitable for the company. The

government disagrees with Yu's argument that the legacy HMC1022

closely resembled other available MMICs, pointing to an email to

a customer in November 2018 in which Yu wrote, "you can hardly

find anything in the market that matches [the TM5051's]

performance." Finally, the government disagrees with Yu's

characterization of the ADI files as an "abandoned prototype,"

arguing that the ADI files gave Yu a "significant leg up" in

creating the TM5051 and TM5052 design layouts.

- 20 -  As with the previous issue, Yu's argument amounts to a

request that we give more weight to his characterization of the

evidence than the prosecution's. But we must view the evidence in

the light most favorable to the prosecution. There was sufficient

evidence here for a rational factfinder to find that the ADI files

"derive[d] independent economic value . . . from not being

generally known . . . and not being readily ascertainable."

18 U.S.C. § 1839(3)(B). A rational juror could conclude that the

ADI files gave Yu a significant advantage in the process of

translating the original HMC1022 microchip; indeed, Yu was

ultimately able to beat ADI's HMC1022A to market. A juror could

also conclude that both ADI and Yu were willing to invest

significant time and money in the translation process because

translation design layouts are valuable.

5. Knowledge

Yu's final sufficiency argument concerns knowledge. He

first argues that a conviction under 18 U.S.C. § 1832 required him

to know that the charged file was a trade secret. In support, he

relies on the district court's instructions to the jury that "the

government must prove not only that the information was in fact a

trade secret, but that Mr. Yu knew it was a trade secret."

Second, Yu contends that prosecutors presented

insufficient evidence of his knowledge that the charged file was

a trade secret. Because reverse-engineering competitors' MMICs

- 21 - was common in the industry and was part of his job at ADI, he

contends that MMIC design features were "readily ascertainable."

Therefore, he argues, while he may have known that keeping ADI's

files breached his employment agreement, he did not know that those

files contained trade secrets.

Additionally, Yu argues that ADI's "Information

Classification Policy" placed "trade secret information" in a

"[s]ecret [n]eed to [k]now" security category. In contrast,

schematics and layouts fell into a lower level of security that

was accompanied by the admonition: "[e]xternal access to this data

should be prevented, but should this data become public, the

consequences are not critical." Therefore, Yu says, he could have

believed that design layout files were confidential and

proprietary but not trade secrets.

In response, the government disagrees that § 1832

requires the prosecution to prove that the defendant knew the

charged trade secret constituted a "trade secret." Even if

knowledge is a required element, the government continues, there

was sufficient evidence of Yu's knowledge here. The government

contends that a juror could reasonably infer that Yu knew the

charged file in his possession was a trade secret from Yu's signed

confidentiality agreements with ADI, his efforts to prevent ADI

from learning he had taken ADI's files, and Yu's request that Win

treat his own file as proprietary.

- 22 -  We need not resolve whether knowledge is a required

element of a charge under § 1832 because we agree with the

government that the evidence was sufficient for a rational juror

to infer that Yu knew the charged file was a trade secret. Yu

signed confidentiality agreements with ADI, promising not to

share, or use for his own purposes, information about ADI's present

and potential products. After taking files from ADI in violation

of this agreement, he tried to conceal his thefts from ADI in

various ways. He renamed the files that he took from ADI,

including renaming the file that included the HMC1022A prototype

from "K8600_TOP.gds" to "Kids8600.jpg" to mask that it was a GDS

file. As he was starting Tricon, while still employed by ADI, he

tried to keep Tricon a "secret" (as he put it to an acquaintance)

so that ADI would not "notice[]" it. He asked Win to treat his

own GDS files as "proprietary" data.

From Yu's actions, including his confidentiality

agreements, his attempts to conceal his personal possession of ADI

files, and his efforts to protect his own files, a juror could

reasonably infer that Yu knew that the charged file was a trade

secret. Cf. United States v. Martin, 228 F.3d 1, 12 (1st Cir.

2000) (finding an agreement to steal trade secrets where the

- 23 - conspirators' actions indicated an intent to gather confidential

and proprietary information).5

Having concluded that the evidence was sufficient to

support the jury's guilty verdict on Count One, we turn to Yu's

equal protection claims.

B. Selective Prosecution

Yu argues that the indictment should have been dismissed

due to selective enforcement and prosecution of Yu based on his

ethnicity, in violation of his Fifth Amendment right to equal

protection. Although there is significant overlap between

selective enforcement and selective prosecution, the legal

standards differ somewhat, and so we address each claim separately.

We begin with the selective prosecution claim, for which the legal

framework is more clearly established. We therefore turn to Yu's

argument that, as a person of Chinese ethnicity, he was selectively

5 In Martin, we examined the sufficiency of the evidence for a conviction of conspiring to steal trade secrets under 18 U.S.C. § 1832(a)(5). See id. at 10-13. As part of proving the conspiracy, the government had to prove "that the defendant possessed both the 'intent to agree and [the] intent to commit the substantive offense.'" Id. at 11 (alteration in original) (quoting United States v. Andújar, 49 F.3d 16, 20 (1st Cir. 1995)). We found sufficient evidence of an agreement to steal trade secrets where the appellant had received "extensive correspondence" that was "marked 'confidential' or 'proprietary,' or [the sender] had expressed some hesitation in forwarding"; had asked the sender to "absorb as much information, physically and intellectually, as you can"; had directed the sender's research with specific questions; and had referred to the sender as his "spy." Id. at 12.

- 24 - prosecuted compared to non-Chinese people, who may face civil suits

when they steal trade secrets but are not prosecuted criminally.

1. Standard of Review

In general, when reviewing a denial of a motion to

dismiss an indictment, "we review legal questions de novo, any

relevant factual findings for clear error, and the court's

'ultimate ruling' for abuse of discretion." United States v.

McGlashan, 78 F.4th 1, 5-6 (1st Cir. 2023) (quoting United States

v. Parigian, 824 F.3d 5, 9 (1st Cir. 2016)). These steps mirror

our multifaceted abuse-of-discretion review. See, e.g., United

States v. Lewis, 517 F.3d 20, 24 (1st Cir. 2008). We have not

previously stated the standard of review for the denial of a

selective prosecution claim, although we have made clear that we

apply abuse-of-discretion review to a district court's denial of

discovery in support of a selective prosecution claim. See id. at

23.

Our sister courts considering denied motions to dismiss

for selective prosecution have largely adopted the same standard

of review stated above; they review factual findings for clear

error and legal conclusions de novo. See, e.g., United States v.

Brantley, 803 F.3d 1265, 1270-71 (11th Cir. 2015); United States

v. Al Jibori, 149 F.3d 125, 127 (2d Cir. 1998); United States v.

Taylor, 686 F.3d 182, 197 (3d Cir. 2012); United States v. White,

928 F.3d 734, 742 (8th Cir. 2019). But see United States v. Rundo,

- 25 - 108 F.4th 792, 798 (9th Cir. 2024) (noting that the Ninth Circuit

"has employed both a de novo standard and a clearly erroneous

standard when reviewing a selective prosecution claim" but

declining to "resolve any purported difference" as unnecessary to

resolving the case before it (quoting United States v. Culliton,

328 F.3d 1074, 1080 (9th Cir. 2003) (per curiam))). Two circuits

describe their standard of review as being for an abuse of

discretion. See United States v. Alanis, 265 F.3d 576, 584 (7th

Cir. 2001); United States v. Alcaraz-Arellano, 441 F.3d 1252, 1265

(10th Cir. 2006). The Sixth Circuit notes that it "generally

review[s]" the refusal to dismiss an indictment for abuse of

discretion, but it reviews the determination of a selective

prosecution claim for clear error because it "is essentially a

factual inquiry." United States v. Jones, 399 F.3d 640, 644 (6th

Cir. 2005).

To resolve any confusion, we hold that when reviewing a

selective prosecution claim, we review legal questions de novo and

factual findings for clear error. Cf. McGlashan, 78 F.4th at 5-6;

United States v. Bucci, 582 F.3d 108, 114-15 (1st Cir. 2009)

(applying abuse-of-discretion review to a claim of vindictive

prosecution, reviewing factual findings for clear error and legal

determinations de novo). As explained in the following section,

a successful claim of selective prosecution requires showing that

similarly situated individuals were not prosecuted. Armstrong,

- 26 - 517 U.S. at 465. We, like the Sixth Circuit, have previously noted

that "determining who constitutes a similarly situated individual"

is a "fact-intensive inquiry." Lewis, 517 F.3d at 24 (citing

Armstrong, 517 U.S. at 466); see Jones, 399 F.3d at 644.

Therefore, much of our review will be for clear error of factual

findings.

We turn to explaining what must be shown for a selective

prosecution claim to succeed.

2. Legal Standard

In general, United States Attorneys have "'broad

discretion' to enforce the Nation's criminal laws." Armstrong,

517 U.S. at 464 (quoting Wayte v. United States, 470 U.S. 598, 607

(1985)). This discretion recognizes that United States Attorneys

"are designated by statute as the President's delegates to help

him discharge his constitutional responsibility to 'take Care that

the Laws be faithfully executed.'" Id. (quoting U.S. Const.,

art. II, § 3). Prosecutorial decisions are supported by a

"presumption of regularity." Id. (quoting United States v. Chem.

Found., Inc., 272 U.S. 1, 14 (1926)). In part, this judicial

deference is due to "an assessment of the relative competence of

prosecutors and courts." Id. at 465.

But prosecutorial discretion is constrained by the

Constitution. Id. at 464. As relevant here, the Fifth Amendment

forbids deciding whether to prosecute "based on 'an unjustifiable

- 27 - standard such as race, religion, or other arbitrary

classification.'" Id. (quoting Oyler v. Boles, 368 U.S. 448, 456

(1962)); see also Bolling v. Sharpe, 347 U.S. 497, 499-500 (1954)

(holding that the Due Process Clause of the Fifth Amendment

contains an equal protection component).

"In order to dispel the presumption that a prosecutor

has not violated equal protection, a criminal defendant must

present 'clear evidence to the contrary.'" Armstrong, 517 U.S. at

465 (quoting Chem. Found., 272 U.S. at 14-15). Making out a claim

of selective prosecution draws on "ordinary equal protection

standards": the defendant must show discriminatory effect and

discriminatory purpose. Id. (quoting Wayte, 470 U.S. at 608).

To "establish a discriminatory effect in a race case,

the claimant must show that similarly situated individuals of a

different race were not prosecuted." Id. "A similarly situated

offender is one outside the protected class who has committed

roughly the same crime under roughly the same circumstances but

against whom the law has not been enforced." Lewis, 517 F.3d at

27 (citing Armstrong, 517 U.S. at 469). When the district court

is determining the pool of similarly situated offenders, "no fact

should be omitted to make [the pool] out completely." Id.

(emphasis omitted) (quoting Armstrong, 517 U.S. at 466). In other

words, "a district court should assess every material fact in

rendering its judgment as to which offenders should be deemed

- 28 - similarly situated," because many factors -- including "the

comparability of the crimes, the similarities in the manner in

which the crimes were committed, the relative efficacy of each

prosecution as a deterrent, and the equivalency of the evidence

against each prospective defendant" -- may legitimately "influence

the government's decision to prosecute one individual but not

another." Id.

To establish discriminatory purpose, the claimant must

show "that the decisionmaker . . . selected or reaffirmed a

particular course of action at least in part 'because of,' not

merely 'in spite of,' its adverse effects upon an identifiable

group." Wayte, 470 U.S. at 610 (alteration in original) (quoting

Pers. Adm'r of Mass. v. Feeney, 442 U.S. 256, 279 (1979)). This

requires "more than . . . intent as awareness of consequences."

Id. (alteration in original) (quoting Feeney, 442 U.S. at 279).

3. Background and Arguments

The district court rejected the selective prosecution

claim because Yu failed to present "clear evidence" of

discriminatory effect.6 Adopting the reasoning of its earlier

order reserving decision on Yu's motion to dismiss, the district

court acknowledged that Yu had listed civil trade secret cases

that the government did not prosecute criminally as well as a case

Yu does not appeal the district court's decision to deny 6

him discovery on his selective prosecution claim.

- 29 - where ADI pursued a civil lawsuit against non-Chinese defendants.

But these comparators were not sufficiently similar, according to

the district court. The district court drew a distinction between

general trade secret theft against American companies, and trade

secret theft where, as here, a party allegedly violated export

controls or passed the stolen trade secrets on to a foreign entity.

Revisiting Yu's motion to dismiss after his trial, the district

court held that Yu had not presented "clear evidence" that

"similarly situated individuals of a different race were not

prosecuted," as required by Armstrong, 517 U.S. at 465.

We first delineate Yu's arguments regarding the

discriminatory-effect prong of his selective prosecution claim.

As he did before the district court, Yu points to a list of cases

from Massachusetts federal and state courts, along with statistics

and research studies that he says show disproportionately high

rates of criminal prosecution for trade secret offenses against

defendants of Chinese ethnicity.

In addition, he highlights three instances to serve as

"control group" comparators. First, he points to a federal civil

lawsuit brought by ADI against another company called MACOM

concerning four former ADI employees, not of Chinese descent, who

allegedly stole the same secrets about MMICs as Yu. According to

Yu, the ex-employees faced no criminal or civil liability; instead,

ADI sued their new employer, and the case quickly settled. Second,

- 30 - Yu states that ADI and a company called Custom MMIC made

"unlicensed 'exports' of GDS design files for 'controlled MMICs to

foreign foundries for manufacture,'" but neither ADI nor the other

company was criminally charged -- unlike Yu. Third, Yu alleges

that the prosecution described various innocuous activities as

"suspicious" when Yu did them but not when a prosecutorial witness

allegedly did the same things.

We now move to Yu's arguments in support of the

discriminatory-intent prong. As discussed in more detail in the

selective enforcement section, Yu points to statements by

President Trump and members of the Trump Administration. As

relevant to his selective prosecution claim, Yu argues that these

statements -- about the danger posed by the Chinese government and

ethnically Chinese individuals stealing trade secrets from U.S.

companies and the need to prioritize prosecutions

accordingly -- are crucial context for understanding the decision

to prosecute him. Yu notes that the day after the United States

Attorney's Office decided to accept law enforcement's referral of

his case, President Trump announced new tariffs on China and

declared, regarding China, "We have a tremendous intellectual

property theft problem." Yu points to post-indictment press

releases and public communications that emphasized that Yu was

"Chinese born." In addition, Yu highlights the prosecution's

attempt to use a peremptory strike against one of two Asian

- 31 - Americans among the group of potential jurors. The prosecutor was

unable to articulate a reason for the strike and withdrew it after

the district court asked why the prosecutor was "challeng[ing] one

of the few Asian Americans on the panel." Finally, Yu notes a

post-verdict press release lauding "the first-ever conviction

following a criminal trial of this kind in the District of

Massachusetts," which, according to Yu, demonstrates "a dramatic

departure from how such disputes between technology companies and

their former employees are typically addressed."

In response, the government focuses (as the district

court did) on the discriminatory-effect prong, addressing several

of the instances that Yu characterized as "control group"

comparators to his own case. Addressing first the ADI case against

MACOM, the government argues that Yu has not presented clear

evidence that the former ADI employees in that case were similarly

situated to him.7 In support, the government explains that those

employees were caught in their attempt to take trade secret

materials, so it was not entirely clear that those materials made

it to MACOM. In the government's view, the quick settlement might

indicate that there was little or weak evidence to support ADI's

7The government also argues that, even though Yu described the requirements for a selective prosecution claim in detail and repeatedly cited Armstrong, we should consider his claim waived because he did not also quote Armstrong's "clear evidence" standard. We decline to adopt such an expansive view of our waiver rules.

- 32 - allegations. In contrast, the government explains, Yu was caught

only after he had converted and profited from the trade secrets he

took, and there was evidence of illegal exports. Next, concerning

Yu's assertion that ADI and Custom MMIC made unlicensed exports of

GDS design files, the government argues that Yu has only asserted,

but has no evidence, that these companies unlawfully exported the

files. The government also distinguishes this situation from Yu's

case, arguing that Custom MMIC's exported GDS files did not contain

stolen trade secrets. Finally, the government addresses the list

of Massachusetts civil trade secrets cases that Yu identifies by

arguing that there is no evidence that the government knew about

those defendants or that those defendants engaged in conduct

comparable to Yu's.

Briefly addressing the discriminatory-purpose prong, the

government casts the Trump Administration's focus on trade secret

theft by China as a legitimate national security focus, rather

than an intent to discriminate based on ethnicity. The government

argues that Yu has not demonstrated that the potential disparate

impact on people of Chinese ethnicity was a reason why the

Executive Branch decided to focus on these prosecutions, as

required to demonstrate discriminatory purpose under Wayte,

470 U.S. at 610. Instead, it characterizes any disparate impact

as a permissible side effect of a legitimate attempt to target the

threat of economic espionage by China. The government dismisses

- 33 - the failed juror challenge and the post-indictment press releases

as irrelevant to the decision to prosecute.

4. Analysis

We begin, as the district court did, with discriminatory

effect. We find no clear error in the district court's findings,

under Armstrong's "fact-intensive inquiry," Lewis, 517 F.3d at 24,

that Yu's proffered comparators were not sufficiently similar. As

the district court noted, Yu offered a list of civil lawsuits

concerning trade secrets that the government did not criminally

prosecute, but Yu did not show that those cases were similar to

his in ways that were more specific than the general category of

trade secrets. Specifically, the district court noted that Yu was

charged with violating export controls and passing the stolen trade

secrets on to a foreign entity. We do not discern any clear error

in how the district court "configured the pool of similarly

situated offenders." Id. at 28. Moreover, although the defense

disputes the district court's findings, Yu cannot show "clear

evidence" of the government declining to prosecute a similarly

situated comparator who allegedly made unlicensed exports

containing stolen trade secrets, or who allegedly passed stolen

trade secrets to a foreign entity. Because the district court did

not clearly err in its factual findings, we also detect no reason

to disturb the district court's conclusion that Yu had not

proffered the "clear evidence" that "similarly situated

- 34 - individuals of a different race were not prosecuted," as required

by Armstrong, 517 U.S. at 465.

We acknowledge the difficulty that a defendant in Yu's

position faces in bringing forth evidence regarding similarly

situated comparators. But this burden reflects the presumption of

regularity that prosecutors are afforded, see Armstrong, 517 U.S.

at 464-65, resulting from "the recognition that the decision to

prosecute is particularly ill-suited to judicial review," Wayte,

470 U.S. at 607. We do not think that the district court erred in

its application of the relevant law, which places a high burden on

the party claiming selective prosecution.

Because we affirm the district court's decision based on

the discriminatory-effect prong, we need not address the

allegations of discriminatory purpose. See Armstrong, 517 U.S. at

465 (requiring both).

C. Selective Enforcement

We now move to Yu's claim that law enforcement singled

him out for investigation due to his ethnicity, in violation of

his equal protection rights.

1. Standard of Review

The First Circuit has not previously laid out a clear

standard of review for the denial of a motion to dismiss an

indictment due to selective enforcement. For the same reasons

explained above regarding selective prosecution, we now clarify

- 35 - that our typical standard of review for denials of a motion to

dismiss an indictment applies to selective enforcement claims: "we

review legal questions de novo[ and] any relevant factual findings

for clear error." McGlashan, 78 F.4th at 5-6; see also

Alcaraz-Arellano, 441 F.3d at 1265 (reviewing denial of motion to

dismiss indictment due to selective enforcement for abuse of

discretion).

2. Legal Standard

"Selective enforcement occurs when police investigate

people of one race but not similarly[ ]situated people of a

different race." Conley v. United States, 5 F.4th 781, 789 (7th

Cir. 2021). Selective enforcement, like selective prosecution,

violates equal protection principles. See Oyler, 368 U.S. at 456;

Whren v. United States, 517 U.S. 806, 813 (1996) ("[T]he

Constitution prohibits selective enforcement of the law based on

considerations such as race" as a violation of equal protection.).

Because the claim is derived from equal protection, it also

requires showings of discriminatory effect and discriminatory

purpose. See Flowers v. Fiore, 359 F.3d 24, 35 (1st Cir. 2004)

(requiring that a plaintiff claiming selective enforcement

"present evidence that he was treated differently from similarly

situated [comparators] and that the action taken against him was

motivated, at least in part, by his race"); see also Conley,

5 F.4th at 789 ("As equal protection claims, both selective

- 36 - prosecution and selective enforcement require proof 'that the

defendants' actions had a discriminatory effect and were motivated

by a discriminatory purpose.'" (quoting Chavez v. Ill. State

Police, 251 F.3d 612, 635-36 (7th Cir. 2001))).

A party claiming selective enforcement "can demonstrate

discriminatory effect by naming a similarly situated individual

who was not investigated or through the use of statistical or other

evidence which 'address[es] the crucial question of whether one

class is being treated differently from another class that is

otherwise similarly situated.'" Farm Lab. Org. Comm. v. Ohio State

Highway Patrol, 308 F.3d 523, 534 (6th Cir. 2002) (alteration in

original) (quoting Chavez, 251 F.3d at 638); see also Conley,

5 F.4th at 796 ("As a general matter, statistics can be 'a useful

tool' that can establish discriminatory effect and provide

powerful evidence of discriminatory intent if race can be isolated

from other confounding variables." (quoting United States v.

Barlow, 310 F.3d 1007, 1011 (7th Cir. 2002))). The familiar Wayte

standard applies for showing discriminatory purpose: that the

relevant decision was made "at least in part 'because of,' not

merely 'in spite of,' its adverse effects upon an identifiable

group." 470 U.S. at 610 (quoting Feeney, 442 U.S. at 279).

Several circuits have considered which evidentiary

standard to apply to selective enforcement claims. The Third and

Fourth Circuits, in cases that did not directly raise that issue,

- 37 - extended Armstrong's "clear evidence" requirement to selective

enforcement claims. See Armstrong, 517 U.S. at 465; United States

v. Washington, 869 F.3d 193, 214 (3d Cir. 2017) ("A defendant

challenging a criminal prosecution at either the law enforcement

or prosecution inflection points must provide 'clear evidence' of

discriminatory effect and discriminatory intent [or purpose].");

United States v. Mason, 774 F.3d 824, 830 (4th Cir. 2014) ("In

light of 'the great danger of unnecessarily impairing the

performance of a core executive constitutional function,'

petitioners must demonstrate 'clear evidence' of racially animated

selective law enforcement." (quoting United States v. Olvis,

97 F.3d 739, 743 (4th Cir. 1996))). The Ninth and Tenth Circuits

have not weighed in explicitly but appear to approve of the clear

evidence standard. See Alcaraz-Arellano, 441 F.3d at 1264

(describing the standard of proof as "demanding" and citing

Armstrong, 517 U.S. at 463); Lacey v. Maricopa Cnty., 693 F.3d

896, 920 (9th Cir. 2012) (same). The Seventh Circuit, in contrast,

when squarely faced with the question of which evidentiary standard

to apply in Conley, adopted the preponderance of the evidence

standard, which is the standard generally applied to equal

protection claims. 5 F.4th at 789-90; see also id. at 790-96

(explaining its decision in detail).

When deciding Yu's selective enforcement claim, the

district court's reasoning coincided with that of the Seventh

- 38 - Circuit; it concluded "that a claim of selective enforcement is

not governed by Armstrong and may be established by a fair

preponderance of the evidence." On appeal, the government

maintains that the district court should have applied the clear

evidence standard but argues that we need not decide this issue

because -- as the district court held -- Yu cannot meet the lower

standard.

The district court's decision that selective enforcement

claims may be proven by a preponderance of the evidence presents

a legal issue that we review de novo. McGlashan, 78 F.4th at 5-6;

see Conley, 5 F.4th at 789.

Armstrong's "clear evidence" standard is required to

rebut "'the presumption of regularity [that] supports' [United

States Attorneys'] prosecutorial decisions." 517 U.S. at 464

(citation modified) (quoting Chem. Found., 272 U.S. at 14-15). We

acknowledge that federal law enforcement falls under the Executive

Branch, and, like prosecutors, law enforcement officers

necessarily exercise discretion. See id. But courts exercise

greater oversight over the decisions of law enforcement officers

than those of prosecutors. Conley, 5 F.4th at 791. Unlike

prosecutors, law enforcement agents regularly testify in courts

and often must "justify their tactics." Id. Law enforcement

officers also may be held civilly liable for alleged constitutional

violations to a greater extent than prosecutors. See id. at 793.

- 39 - Prosecutors are granted absolute immunity from claims for damages.

See Imbler v. Pachtman, 424 U.S. 409, 427 (1976) (absolute civil

immunity for actions taken in the prosecutorial role). But law

enforcement officers receive qualified immunity, a lower level of

protection from civil claims for damages. See Conley, 5 F.4th at

793; Kalina v. Fletcher, 522 U.S. 118, 126-27 (1997) (holding that

prosecutors receive only qualified immunity when "perform[ing] the

investigative functions normally performed by a detective or

police officer" and noting that "the senior law enforcement

official in the Nation -- the Attorney General of the United

States -- is protected only by qualified, rather than absolute,

immunity when engaged in the performance of national defense

functions rather than prosecutorial functions"). Because law

enforcement officers are subject to greater judicial scrutiny, we

conclude that the reasoning laid out in Armstrong, requiring "clear

evidence" that a prosecutor has violated equal protection, does

not extend to selective enforcement claims. Cf. 517 U.S. at 465.

We agree with the district court and the Seventh Circuit that

selective enforcement claims must be proven only by a preponderance

of the evidence.8

8 We also agree with the Seventh Circuit that applying a preponderance standard does not necessarily create a circuit split, since other circuits that have "cited Armstrong's clear-evidence standard when assessing selective-enforcement claims" have "invoked Armstrong in passing without specifically rejecting a preponderance standard." Conley, 5 F.4th at 796 n.4.

- 40 -  3. Background and Arguments

After allowing limited discovery on the selective

enforcement claim and hearing oral argument, the district court

concluded that Yu had failed to meet his burden by a preponderance

of the evidence and denied his motion to dismiss the indictment.

The district court found Yu's motion "troubling" because "there

[was] not insignificant evidence" of "not explicit discrimination

against Mr. Yu, but implicit bias based upon his ethnic heritage."

The district court also stated that the fact that Yu was from China

"played a role in part in what happened here." The district court

noted a rise in anti-Asian racism in the United States since 2016.

However, the district court deferred to the Executive Branch's

decision to prioritize the threat of U.S. intellectual property

theft by China and explained that this deference was particularly

appropriate in the areas of national security and foreign affairs.

The district court concluded that even if Yu were not from China

or of Chinese descent, law enforcement officers likely would have

investigated his possession of stolen MMIC designs, which have

potential military uses and are manufactured in Taiwan.

On appeal, in making the case for discriminatory effect,

Yu points to the same evidence marshalled for his selective

prosecution claim: the civil lawsuits that he contends show that

non-Chinese people were not investigated despite their similar

conduct to the allegations against him. Yu emphasizes the MACOM

- 41 - case, in which former ADI employees stole trade secrets that

included MMIC design files but were apparently not investigated.

Regarding discriminatory purpose, Yu points to the

Department of Justice's statements of intention to aggressively

prosecute China's efforts to steal trade secrets from the United

States. Yu quotes then-Massachusetts U.S. Attorney Andrew

Lelling, at that time one of five members of the Department of

Justice's China Initiative Steering Committee, as saying, "[T]hat

rival nation [that is trying to steal U.S. technology] is made up

almost exclusively of Han Chinese. And so, unfortunately, a lot

of our targets are going to be Han Chinese. If it were the French

government targeting U.S. technology, we'd be looking for

Frenchmen."

Yu argues that law enforcement in his case overreacted

to two anonymous "tips" because agents assumed, based on his

ethnicity, that he had a nexus to China. For example, in a "Defense

Counterintelligence and Security Agency" report, investigators

categorized one of these tips as "foreign intelligence" because Yu

was "reasonably believed" to be "acting on behalf of[] a foreign

power." The FBI similarly categorized Yu's open case as "foreign

counterintelligence" related to China. The Department of Homeland

Security described his case as "significant" and listed it, among

others, in a memo about "[t]he Chinese [t]hreat." Law enforcement

noted that Yu had visited China recently and that he had graduated

- 42 - from Tsinghua University, one of the top universities in China,

which one report described as "actively support[ing] numerous

Chinese military programs and research[ing] subjects of military

interest." Yu characterizes this as "suspicion by association,"

comparing it to suggesting that every graduate of MIT is an "agent"

of the U.S. government.

Yu argues that the district court committed legal error

when it denied his motion to dismiss for selective enforcement

after effectively making, in Yu's description, a factual finding

of implicit bias. Yu contends that based on this factual finding,

the district court should have concluded that law enforcement

referred Yu for prosecution at least in part "because of" his

ethnicity, demonstrating discriminatory purpose under Wayte, 470

U.S. at 610. Yu also contends that the district court clearly

erred in finding no "explicit discrimination" (in the district

court's words) in light of Yu's evidence.

Regarding discriminatory effect, the government first

argues that Yu failed to establish his case using statistics

because he did not identify similarly situated non-Chinese people

in possession of stolen trade secrets whom the agents knew about

and declined to investigate. Second, the government argues that

even after receiving discovery, Yu failed to show that the

investigators in his case would not have opened the case or

referred it for prosecution if not for his ethnicity. The

- 43 - government disagrees that the district court made a factual finding

of discriminatory effect, arguing that its statement that Yu's

ethnicity "played a role in part in what happened here" did not

rise to a finding of but-for causation.9 The government also

argues that, based on the evidence, the district court did not

clearly err in finding that law enforcement would have investigated

someone with Yu's conduct and ties to China10 who was not of Chinese

ethnicity.

Regarding discriminatory purpose, the government

maintains that it was legitimately concerned about economic

espionage by China. Therefore, the government claims, it was also

legitimate to investigate someone with Yu's ties to China who had

allegedly stolen trade secrets that contained "sensitive

technology." The government argues that the district court's use

9 Discussingcausation in the context of discriminatory effect confuses the issues. Causation fits more squarely within the discriminatory-purpose analysis. See Wayte, 470 U.S. at 610 (articulating that the discriminatory-purpose standard requires a decisionmaker to "select[] or reaffirm[] a particular course of action at least in part 'because of,' not merely 'in spite of,' its adverse effects upon an identifiable group" (quoting Feeney, 442 U.S. at 279)). 10Specifically, the government points to evidence that Yu was actively seeking to do business in China, including evidence that Yu mentioned that he had an agent in China; that Yu asked a contact in China to promote the Tricon website because he was "trying to see if [he] can expand to China"; and, in response to his contact writing him to "[h]urry up, return to China and start a business," that Yu responded that he "will definitely return to serve the country" "when [he is] ready."

- 44 - of the term "implicit bias" does not rise to what the government

describes as Wayte's requirement that discriminatory intent be

"deliberate[]" and "purpose[ful]." See 470 U.S. at 608. Finally,

the government argues that the fact that Yu's ties, "upon further

investigation[,] turned out not to extend to the Chinese government

does not retroactively invalidate the investigation"; nor was the

government required to end its prosecution of the federal crimes

it uncovered even though it "did not find evidence of the feared

economic espionage crime."

4. Analysis

Although the district court did not delineate its

conclusions in terms of discriminatory effect and purpose, its

reasoning encompassed both elements. Because we find no clear

error in the district court's factual findings undergirding its

determination that there was no discriminatory effect, we affirm.

See McGlashan, 78 F.4th at 5-6.

The district court effectively concluded that Yu failed

to meet his burden because he did not show that "one class [was]

being treated differently from another class that [was] otherwise

similarly situated." See Farm Lab. Org. Comm., 308 F.3d at 534

(quoting Chavez, 251 F.3d at 638). The required analysis is two-

fold: the proffered comparators must be both similarly situated

and treated differently. See id. (emphases added); see also

Flowers, 359 F.3d at 35. In detailing its factual findings, the

- 45 - district court noted several factors that weighed importantly in

its decision. First, the MMICs at issue in Yu's case had a

"potential military use." Second, considering foreign policy

concerns over China's involvement in the theft of "U.S.

intellectual property, industrial secrets, and personal data," the

officers investigating Yu's case "rationally . . . perceived . . .

a potential threat with respect to a foreign nation." And third,

Yu's case was affirmatively tipped off to law enforcement.

Regarding the technologies at play and the connections

to China among Yu's proffered comparators, Yu's point that the

MACOM case, like his, involved "sensitive military technologies"

and a company with a "presence in China" is well-taken. Indeed,

this suggests some similarities between Yu's case and his

comparators. But Yu does not show (or even argue to us on appeal)

that the government knew about these comparators and then declined

to investigate. See Farm Lab. Org. Comm., 308 F.3d at 534. This

is fatal to his claim.

Instead, Yu argued (and only before the district court)

that "investigators . . . could have, and should have[] known"

about MACOM's theft of trade secrets. Yu therefore has not shown

that these comparators are similarly situated, i.e., that they

"ha[ve] committed roughly the same crime under roughly the same

circumstances." Lewis, 517 F.3d at 27. Nor has he shown that law

enforcement treated them differently by purposefully opting not to

- 46 - investigate. Id. In Yu's case, in contrast, as the district court

explained, the limited information and evidence available to the

government at the pre-indictment stage supported opening and

continuing an investigation into his actions. We therefore see no

reason to disturb the district court's conclusion that there was

no discriminatory effect here.

Because we affirm the district court's holding of no

discriminatory effect, we need not analyze discriminatory

purpose.11 See Flowers, 359 F.3d at 35 (requiring both prongs for

a successful claim of selective enforcement).

IV. Conclusion

For the reasons above, we affirm the conviction.

11 Because we affirm the district court's denials of Yu's selective enforcement and prosecution claims, we need not decide whether the correct remedy for successful claims would be dismissal of the criminal proceedings.

- 47 -