1

UNITED STATES DISTRICT COURT

FOR THE DISTRICT OF COLUMBIA

__________________________________

)

UNITED STATES OF AMERICA )

)

v. ) Criminal No. 10-256-08, -09, -20 (RMC)

)

NOE MACHADO-ERAZO, )

JOSE MARTINEZ-AMAYA, and )

YESTER AYALA, )

)

Defendants. )

_________________________________ )

OPINION

The three Defendants in this criminal case, Noe Machado-Erazo, Jose MartinezAmaya, and Yester Ayala, are charged with offenses related to their involvement in the 

transnational gang MS-13. Prior to trial, the government sought special protection for its 

potential expert witness on MS-13’s operations and structure. That potential witness—identified 

here as Juan Diaz—is a member of the Salvadoran National Civil Police who lives in El Salvador 

and works in gang enforcement. The government feared violent reprisal against him and his 

family if he were identified publicly as giving testimony against MS-13, which remains 

extremely powerful and dangerous in his home country. The government asked the Court to 

permit the Mr. Diaz to testify using a pseudonym and to limit the extent of required disclosure of 

Mr. Diaz’s personal information to the Defendants and their counsel. Following a sealed ex 

parte hearing on June 17, 2013, the Court granted the government’s motion. The Court now 

writes to expand on the reasoning for its decision. 
2

I. FACTS

The Defendants are among twenty persons charged with offenses related to 

alleged involvement in MS-13 in United States v. Silva, Criminal No. 10-256 (RMC).1 In the 

most recent Superseding Indictment, Dkt. 330, Defendants are charged with, inter alia, 

involvement in a conspiracy to violate the Racketeer Influenced and Corrupt Organizations Act 

(“RICO”), 18 U.S.C. §§ 1961–68, that began “at least” as early as “the late 1990s” and that 

continues to the present. Superseding Indictment [Dkt. 330] ¶ 16. “MS-13, including its 

leadership, members and associates, in the District of Columbia, Maryland, El Salvador, and 

elsewhere” are the alleged RICO “enterprise.” See id. ¶ 13. 

The government describes MS-13 as follows:

La Mara Salvatrucha, also known as the MS-13 gang (hereafter 

“MS-13”), is a gang composed primarily of immigrants or 

descendants of immigrants from El Salvador, with members 

operating throughout the United States, including within the 

District of Columbia. The name “Mara Salvatrucha” is a 

combination of several slang terms. The word “Mara” is the term 

used in El Salvador for “gang.” The phrase “Salvatrucha” is a 

combination of the words “Salva,” which is an abbreviation for 

“Salvadoran,” and “trucha,” which is a slang term for the warning 

“fear us,” “look out,” or “heads up.”

. . .

MS-13 is a national and international criminal organization with 

over 10,000 members regularly conducting gang activities in at 

least twenty states and the District of Columbia, as well as in 

Mexico, Honduras, Guatemala, and El Salvador. MS-13 is one of 

the largest street gangs in the United States. Gang members 

actively recruit members, including juveniles, from communities 

with a large number of immigrants from El Salvador. Members, 

however, can also have ethnic heritage from other Central 

 1 Because other co-defendants have pled guilty, are pending extradition, or (in one case) had all 

federal charges dismissed, Messrs. Machado-Erazo, Martinez-Amaya, and Ayala are the only 

remaining active defendants. 
3

American countries. In the United States, MS-13 has been 

functioning since at least the 1980s.

. . .

[M]embers of MS-13 were expected to protect the name, 

reputation, and status of the gang from rival gang members and 

other persons. MS-13 members required that all individuals should 

show respect and deference to the gang and its membership. To 

protect the gang and to enhance its reputation, MS-13 members 

were expected to use any means necessary to force respect from 

those who show disrespect, including acts of intimidation and 

violence. MS-13’s creed is exemplified by one of its mottos, 

“Matar, robar, violar, controlar,” which translates in sum and 

substance to, “Kill, steal, rape, control.”

. . .

MS-13 members were required to commit acts of violence to 

maintain membership and discipline within the gang, including 

violence against rival gang members or those they perceived to be 

rival gang members, as well as MS-13 members and associates 

who violated the gang’s rules. As a result of MS-13’s frequent use 

of violence, innocent persons were often injured or killed. 

Participation in criminal activity by an MS-13 member, 

particularly violent acts directed at rival gang members or as 

ordered by the gang leadership, increased the level of respect 

accorded that member, resulting in that member maintaining or 

increasing his position in the gang, and possibly resulting in 

recognition as a leader

Id. ¶¶ 1, 3, 6, 7.

On February 1, 2012, well in advance of any of the scheduled trial dates in this 

case, the government filed a Motion for Protective Order as to Proposed Expert Witness, Dkt. 

114.2

 See also Gov’t Notice of Intent to Pursue Mot. [Dkt. 282] (stating that government would 

pursue the protective-order motion in connection with the trial of these three defendants). In its 

motion, the government asked the Court’s permission “to withhold the identity and personal 

 2 The defendants were divided into groupings for trial. See, e.g., Second Minute Order dated 

Nov. 4, 2011. The earliest trial date would have been September 24, 2012. As of this date, only 

the remaining three active Defendants have proceeded to trial. 
4

information of a proposed expert witness,” Juan Diaz, whom the Government anticipated

offering as an expert witness “on the leadership, nature and activities of MS-13 in El Salvador 

[and] its relationship to MS-13 in the United States.” Mem. Supp. Gov’t Mot. (“Gov’t Mem.”) 

[Dkt. 114-1] at 1, 6. The government disclosed a summary of Mr. Diaz’s qualifications and 

proposed testimony to defendants pursuant to Rule 16(a)(1)(6), but it asserted that “disclosure of 

the witness’s true name, residence, place of birth, or specific place or manner of employment . . . 

would expose this witness and/or his family unnecessarily to serious danger from retaliation.” 

Id. at 6. The government also submitted a one-page affidavit from Juan Diaz under seal. See

Gov’t Notice of Filing (“Diaz Aff.”) [Dkt. 117]. 

Defendants filed an opposition on March 15, 2012, contending that their 

Confrontation Clause rights under the Sixth Amendment required the Court to deny the 

government’s request.

3

 See Def. Opp. [Dkt. 128]. They argued that they needed access to Juan 

Diaz’s true identity because without it, “defense counsel would be forced to leave the broad, selfserving representations made by the government and ‘Juan Diaz’ unchallenged, as defense 

counsel would not be able to conduct any independent investigation” into, inter alia, Mr. Diaz’s 

credentials as an expert or potential impeachment material. Id. at 7. 

The Court first addressed the government’s motion at a motions hearing held on 

March 13, 2013. On that date, the Court reserved ruling on the motion and scheduled an ex 

parte, sealed hearing to “evaluate the extent of the danger faced by the government’s proposed 

expert witness.” See March 13, 2013 Order [Dkt. 305] at 1. On June 17, 2013, the day before 

 3 The opposition was filed on behalf of another defendant, Omar Aguilar, by Mr. Aguilar’s 

counsel, Paul Kiyonaga and John Carney. The remaining three Defendants adopted Mr. 

Aguilar’s opposition. 
5

trial began, the Court held the ex parte, sealed hearing, at which Juan Diaz testified.4

 At the 

hearing, Mr. Diaz expanded upon the information set forth in his sealed affidavit. The Court 

summarizes his sworn affidavit and testimony in a general manner in this Opinion without 

providing details that could be used to determine his identity. 

Mr. Diaz is a seventeen-year veteran of Salvadoran National Civil Police who 

presently holds the rank of investigator. His work includes investigating gangs, including MS-13 

and 18th Street (Calle Dieciocho in Spanish). Mr. Diaz explained that members of Salvadoran 

gangs, including MS-13, have put out kill orders, referred to as “green lights,” for members of 

Salvadoran law enforcement who investigate gang activity. He also identified several examples 

of menacing or violent activity undertaken by gangs with the express goal of intimidating law 

enforcement, including during off hours or while law enforcement agents are at home. In his 

affidavit, for example, Mr. Diaz identified an incident in late 2010 in which gang members in El 

Salvador made videos threatening to harm judges, prosecutors, and government agents. He also 

identified an incident on January 16, 2012, in which a 36-year-old, 10-year police veteran named 

Juan Carlos Zepeda Burgos was killed in Ciudad Arce in El Salvador, and an incident on 

February 14, 2011, in which Agent Hugo Max Gonzalez Rubio was killed in Apopa, El 

Salvador, his body left in the street in a black plastic bag. According to Mr. Diaz, homicides of 

police officers in El Salvador have increased since 2010.5

 4 Due to an unanticipated medical emergency, the case was transferred to Chief Judge Royce C. 

Lamberth for trial following jury selection (held on June 14, 2013) and resolution of all pretrial 

motions. 

5 The government also observes: “In United States District Court for the Central District of 

California, MS-13 members were indicted for, amongst other counts, conspiring to murder a Los 

Angeles gang task force officer; that case is pending trial. On July 15, 2011, Walter TorresDuke, a member of MS-13, pled guilty in United States District Court for the Eastern District of 

New York, to conspiring to murder an ICE agent who had investigated cliques in the Long Island 

area.” Gov’t Mem. at 2. 
6

Mr. Diaz explained that, in trials in El Salvador, the names of witnesses whose 

safety might be endangered are generally not disclosed. Instead, they are permitted to testify 

using code names and numbers. He also explained that, while gangs often tolerate police 

testimony in El Salvador, his proffered testimony in this case would be different and would 

likely result in MS-13 issuing a green light against him for two reasons. First, gangs distinguish 

between fact testimony given by officers about investigations they conducted personally, which 

is seen as routine and fair, and expert testimony about MS-13 generally, which is viewed as a 

provocation and is more likely to cause retribution. Second, MS-13 members believe that only 

members may discuss the gang’s rules, so having a police officer testify about those rules in 

court would be seen as a challenge to the gang. 

Mr. Diaz explained that he and his family would be at risk if his real name or 

identifying information were released, noting that senior members of MS-13 are aware of cases 

in the United States involving MS-13 and would be likely to learn of his involvement. Asked by 

the Court how serious the danger was, Mr. Diaz testified: “It would be a serious risk for me . . . if 

it were an open case, if my name were to come out or my picture were to come out.” He also 

stated that, because of MS-13’s presence in the United States, the gang would be required to 

carry out a green light in either country. 

At the conclusion of the hearing, the Court granted the government’s motion, 

noting that “Mr. Diaz’s testimony established imminent and grave risk to his safety and his 

family’s safety if his real name were used.” See June 17, 2013 Protective Order [Dkt. 372] at1. 

The Court directed that Mr. Diaz be permitted to testify at trial under pseudonym, that the 

government could withhold from Defendants and their counsel Mr. Diaz’s true identity 

(“including but not limited to: home and work address, specific employment, date of birth, El 
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Salvadoran identification number, and place of birth”), and that “counsel for Defendants [could]

not in any way seek to elicit testimony or seek to admit evidence before the jury concerning the 

expert witness’s true identity or the fact that his identity before the jury [was] a pseudonym.” Id.

at 1–2. 

Mr. Diaz testified at trial on June 18 and 20, 2013. The Court permitted him to 

offer testimony as an expert “on MS-13 in El Salvador, its structure, its rules and activities.” 

June 18, 2013 P.M. Trial Tr. at 10, 15. As proffered by the government, Gov’t Mem. at 3, he did 

not “testify about any particular defendant or his activities.” Although counsel for Mr. MachadoErazo conducted a voir dire of Mr. Diaz, no defendant objected to Mr. Diaz testifying as an 

expert. The Court has not been made aware of any issues of compliance with the protective 

order.

II. ANALYSIS

A. The Nature of the Right of Confrontation

“In all criminal prosecutions, the accused shall enjoy the right . . . to be 

confronted with the witnesses against him.” U.S. Const. amend. VI. The Confrontation Clause 

guarantees criminal defendants the right to confront witnesses offering testimonial evidence in

court and to cross-examine those witnesses. See Crawford v. Washington, 541 U.S. 36, 51 

(2004) (“[T]he principal evil at which the Confrontation Clause was directed was the civil-law 

mode of criminal procedure, and particularly its use of ex parte examinations as evidence against 

the accused.”). Defendants thus generally have the right to question an adverse witness about 

identifying information, including name and address. See Smith v. Illinois, 390 U.S. 129, 131 

(1968) (“[T]he very starting point in exposing falsehood and bringing out the truth through crossexamination must necessarily be to ask the witness who he is and where he lives.”). The right to

a witness’s identity, however, is not absolute. See, e.g., Chavis v. North Carolina, 637 F.2d 213, 
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226 (4th Cir. 1980) (“[C]ases have held that a trial court may limit cross-examination if the 

information sought could endanger the witness.”); Smith, 390 U.S. at 133–34 (instructing that a 

trial court may limit otherwise permissible questions if they would endanger the witness) (White, 

J., concurring). 

As the Supreme Court stated in the context of requiring the government to reveal 

the identity of a non-testifying confidential informant:

We believe that no fixed rule with respect to disclosure is 

justifiable. The problem is one that calls for balancing the public 

interest in protecting the flow of information against the 

individual’s right to prepare his defense. Whether a proper balance 

renders nondisclosure erroneous must depend on the particular 

circumstances of each case, taking into consideration the crime 

charged, the possible defenses, the possible significance of the 

informer’s testimony, and other relevant factors.

Roviaro v. United States, 353 U.S. 53, 62 (1957). 

In balancing the defendants’ ability to cross-examine effectively with a witness’s 

safety, a number of cases have held that a trial court may protect the true identity of a testifying 

witness for that witness’s safety. See United States v. Ramos-Cruz, 667 F.3d 487, 500 (4th Cir. 

2012); United States v. El-Mezain, 664 F.3d 467 (5th Cir. 2011); Siegfriedt v. Fair, 982 F.2d 14, 

17 (1st Cir. 1992); United States v. Rangel, 534 F.2d 147, 148 (9th Cir. 1976); United States v. 

Palermo, 410 F.2d 468, 472 (7th Cir. 1969) (“[W]here there is a threat to the life of the witness, 

the right of the defendant to have the witness’ true name, address and place of employment is not 

absolute. . . . Under almost all circumstances, [however,] the true name of the witness must be 

disclosed.”); cf. Delaware v. Van Arsdall, 475 U.S. 673, 679 (1986) (Trial judges possess “wide 

latitude . . . to impose reasonable limits on . . . cross-examination based on concerns about, 

among other things, harassment, prejudice, confusion of the issues, the witness’[s] safety, or 

interrogation that is repetitive or only marginally relevant.”). In such cases, the government 
9

bears the burden in demonstrating “that the threat to the witness is actual and not a result of 

conjecture.” Ramos-Cruz, 667 F.3d at 500 (quoting Palermo, 410 F.2d at 472). In doing so, the 

government need not tie a threat to specific defendants. See United States v. Celis, 608 F.3d 818, 

832 (D.C. Cir. 2010) (“The appropriateness of using pseudonyms to protect witnesses does not 

depend on whether the threat to the witness comes directly from a defendant or from another 

source.”). To the extent possible, however, courts encourage disclosure of background material 

to defendants to permit cross-examination to be as effective as possible. E.g., El-Mezain, 664 

F.3d at 492 (“The Government disclosed to the defense over twenty volumes of material that Avi 

used to formulate his expert opinion about Hamas financing. Moreover, the Government agreed 

in pretrial filings that the defense would be permitted to ask Avi about his background, his 

training and experience with the ISA, his legal education, and his potential bias in favor of 

Israelis in the West Bank.”). 

B. Factually Similar Fourth & D.C. Circuit Cases 

The government relies heavily on Fourth Circuit precedent endorsing the exact 

procedure it proposes here with respect to expert testimony offered in trials in the District of 

Maryland by this same Juan Diaz. See Gov’t Mem. at 3–4. The government explains:

In August 2005, in the District of Maryland, one of the first 

indictments charging MS-13 members with RICO conspiracy and 

other racketeering acts was returned against more than twenty MS13 members. Several trials were held over the years, resulting in 

convictions for RICO conspiracy, VICAR murder and assault, and 

other crimes against all those who had been indicted. The El 

Salvadoran police officer who has been noted as an expert in the 

instant case testified at many of those trials, using the pseudonym 

“Juan Diaz.” During the discovery process for each trial, the 

Honorable Deborah Chasanow, a United States District Judge for 

the District of Maryland, after reviewing affidavits and receiving in 

camera testimony from [Mr.] Diaz, issued a protective order 

permitting the government to withhold Juan Diaz’s actual identity 

from the defense. Moreover, the court ruled each time that [Mr.] 

Diaz could testify under the pseudonym because revealing his 
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name or other personal information could pose a substantial risk to 

his or his family’s safety. [Mr.] Diaz testified in those trials about 

the nature and activities of MS-13 in El Salvador; he did not testify 

about any particular defendant or his activities.

Id. (citing United States v. Cruz et al., Cr. No. 8:05-cr-393-DKC (D. Md. filed Aug. 23, 2005)).

The Fourth Circuit upheld complete withholding of Juan Diaz’s true identity in 

different trials on three occasions: United States v. Argueta, 470 F. App’x 176, 179–80 (4th Cir.), 

cert. denied, 133 S. Ct. 524 (2012); United States v. Ramos-Cruz, 667 F.3d 487, 500–01 (4th Cir. 

2012) (no petition for certiorari filed); United States v. Zelaya, 336 F. App’x 355, 357–58 (4th 

Cir. 2009), cert. denied, 130 S. Ct. 2341 (2010). 

The Fourth Circuit’s first decision was in Zelaya, in which the court stated that a 

judge can restrict information about a witness on cross-examination if the government showed a 

danger to the witness’s safety that was “actual and not a result of conjecture.” 336 F. App’x at 

358 (quoting Palermo, 410 F.2d at 472). When the government makes such a showing, the judge 

must then determine “whether the information must be disclosed in order not to deny effective 

cross-examination.” Id. (quoting Palermo, 410 F.2d at 472). Applying that standard, the Zelaya

court held:

Our review of the appellate briefs and the sealed affidavits, as well 

as the sealed transcripts of an ex parte and in camera hearing in 

which the district judge conducted an examination of the 

witnesses, persuade us that the district court did not abuse its 

discretion in preventing the defendants from learning the true 

identity of the two El Salvadorian government witnesses. The 

information provided to the district court indicated that the threat 

to these witnesses and their families, should their true identities be 

provided, was “actual and not a result of conjecture.” 

Furthermore, the government disclosed to the defense details of 

these two witnesses, including a pretrial notice regarding the nature 

of their testimony and a transcript of their previous sworn 

testimony on the same subject matter presented in this case. This 

information enabled the defendants to effectively cross-examine 

the witnesses without threatening their safety.
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Id. (citation omitted). 

In Ramos-Cruz, the Fourth Circuit adopted the reasoning of Zelaya and upheld the 

district court’s decision to withhold “Juan Diaz’s” (and one other witness’s) true identity from 

defense counsel and to permit pseudonymous testimony. Ramos-Cruz, 667 F.3d at 500–01. The 

convictions were affirmed unanimously, but one judge dissented from the panel’s holding on the 

pseudonymous-testimony issue.

In Ramos-Cruz, the witnesses submitted in camera affidavits “explaining the 

specific threat to them were their identities revealed.” Id. at 501. Because the affidavits were 

sworn in 2006 and 2007, well in advance of trial, the district court “conducted an ex parte

hearing and examined the two El Salvadorian officers to determine whether the disclosure of 

their names, addresses, or dates and places of birth to the defendant would continue to pose a 

danger to the officers and their families.” Id. At the hearing, the district court concluded that the 

threat was still extant and granted the requested protective order.

Ramos-Cruz found no abuse of discretion in withholding the witnesses’ identities. 

The court found that the witnesses “specifically explained the heightened level of danger to 

which El Salvadorians who testify against MS-13 in U.S. Courts are subject. They then 

connected that threat to the specific investigative work they perform.” Id. Such specificity was 

sufficient to grant the protective order. Id. The Ramos-Cruz court also emphasized “the limited 

focus of the witnesses’ testimony.” Id. The witnesses did not offer any direct evidence 

involving Mr. Ramos-Cruz or his activities; instead, “[t]hey merely provided background 

information about the internal working of MS-13 generally.” Id.

The Fourth Circuit treated Argueta as a straightforward case in which RamosCruz “controlled.” 470 F. App’x at 179. It again found “no abuse of discretion in the district 

court’s decision to allow Mr. Diaz to testify under the pseudonym without disclosing any 
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identifying information to Argueta’s defense counsel.” Id. at 180. In reaching that conclusion, 

the Fourth Circuit stated:

As was the case in Ramos–Cruz, the government provided Argueta

with the substance of Mr. Diaz’s testimony, which concerned only 

general information regarding the MS–13 gang operations and did 

not specifically involve Argueta. The government also provided 

Argueta with transcripts of the witness’s testimony in prior cases. 

Furthermore, the district court conducted an in camera review of 

affidavits attesting to the personal and professional safety 

implications of disclosing Mr. Diaz’s true identity and conducted 

an ex parte hearing regarding the continuing danger to Mr. Diaz 

and his family. Based on this evidence of an actual threat to Mr. 

Diaz’s safety, the district court allowed his testimony under the

pseudonym.

The defendants in this case argue that relying on the Fourth Circuit cases is 

inconsistent with the D.C. Circuit’s opinion in United States v. Celis, 608 F.3d 818 (D.C. Cir. 

2010).6

 In Celis, the government sought a protective order from the district court similar to the 

one sought here. Id. at 829 (“[T]he government had filed under seal a motion in limine seeking a 

protective order barring the release of the true identities of witnesses from Colombia and 

allowing these witnesses to testify under pseudonyms.”). The district court granted the motion in 

part. Instead of completely protecting the identities of the witnesses, the trial judge required the 

government, seven days before the witness was to testify, to disclose the witnesses’ true 

identities to defense counsel, the defendant, and one member of the defense team located in the 

United States. Id. The true identities could also be shared with individuals in Colombia but only 

with prior approval from the Court. Id. Finally, the witnesses were allowed to testify under 

pseudonyms. Id. 

 6 The defendants in Celis were associated with Fuerzas Armadas Revolucionaras de Colombia

(“FARC”), “the most significant drug trafficking organization in Colombia.” Celis, 608 F.3d at 

826. 
13

On appeal, the D.C. Circuit approved the use of the protective order based on the 

specific facts of that case. See 608 F.3d at 833 (“The protective order and its management by the 

district court reflect an appropriate balancing of interests in the relevant case-specific context in 

view of the factors described in Alford and Smith as well as Roviaro, 353 U.S. at 61–62”). The 

Celis court reasoned: 

The district court balanced the reality of potentially life-threatening 

dangers to the protected witnesses and their families, and the 

defense need to prepare to cross-examine the protected witnesses 

by allowing defense access to the true identities of the protected 

witnesses days before their testimony and, when shown to be 

necessary for those purposes, allowed investigation using these 

true identities in the United States and in Colombia.

Id.

C. Application to this Case

Defendants’ opposition to the procedure proposed by the government depends on 

the argument that this Circuit’s precedent, Celis, is inconsistent with the Fourth Circuit’s 

precedent in Ramos-Cruz and the related cases. See Def. Opp. at 5 (“[T]he Ramos-Cruz and 

Zelaya opinions[ ] are inconsistent with the jurisprudence of the Supreme Court as demonstrated 

above and do not reflect the law in this Circuit.”). Put another way, Defendants assert that Celis

stands for the proposition that complete withholding of a witness’s true identity is impermissible

in the D.C. Circuit; instead, at the very least, the defense must have at least some access to the 

real name of the witness for investigative purposes. Id. (arguing that Celis “affirmed the use of 

pseudonyms during testimony primarily because the true identities of the witnesses were shared 

with defense counsel”). 

Closer reading of Celis confirms that the D.C. Circuit was not adopting a per se

rule requiring disclosure of a witness’s true identity. The Celis court endorsed the procedure 

followed by the district court on the facts of that case, 667 F.3d at 833 (referring to “an 
14

appropriate balancing of interests in the relevant case-specific context”), but it did not purport to 

make that procedure a binding minimum standard of disclosure. Thus, Celis is consistent with 

Ramos-Cruz and the Fourth Circuit cases, establishing that the district court must balance 

witness safety with a need to give meaning to the Confrontation Clause right. Id. (“The 

protective order and the district court’s management of it involved a delicate balancing of 

interests necessitated by extraordinary circumstances warranting special measures to protect key 

witnesses”). Celis cautions that courts must make careful factual findings, doing everything 

possible to make sure that defendants receive the information that they can, but it does not create 

a per se rule of disclosure. 

“[T]aking into consideration the crime charged, the possible defenses, the possible 

significance of the informer’s testimony, and other relevant factors,” and after “balancing the 

public interest in protecting the flow of information against the individual’s right to prepare his 

defense,” see Roviaro, 353 U.S. at 62, the Court granted the government’s motion because the 

threat to Juan Diaz is “actual and not a result of conjecture.” Ramos-Cruz, 667 F.3d at 500. 

Review of Mr. Diaz’s affidavit, as well as his testimony at the sealed ex parte hearing, 

demonstrated that Salvadoran law enforcement agents who provide testimony against MS-13 

face a grave and immediate danger of violent, likely fatal, retribution. This showing is at least as 

great as that accepted by the Fourth Circuit in Ramos-Cruz and the related cases. See id. at 501 

(“The witnesses here, however, specifically explained the heightened level of danger to which El 

Salvadorians who testify against MS–13 in U.S. courts are subject. They then connected that 

threat to the specific investigative work they perform in El Salvador. We believe that this level of 

specificity is sufficient.”). Crucially, Mr. Diaz testified that the danger to law enforcement 

officers who testify against MS-13 is ongoing and, in fact, has increased since 2010. He also 
15

made clear that, because MS-13’s reach crosses the thousands of miles between the United States 

and El Salvador, gang members are quite capable of learning of his expert testimony in this case 

and, if they did, would likely retaliate because they would view it as a threat or provocation, far 

more threatening to them than his normal investigative work in El Salvador. The Court thus 

found that Juan Diaz, as well as his family, would face grave, actual danger if he were to give the 

proffered testimony under his true name. 

The inquiry thus shifted to whether the Defendants’ right to cross-examination 

could be preserved without access to Juan Diaz’s true identity. See El-Mezain, 664 F.3d at 492 

(discussing nature of information disclosed to the defense and concluding that the “defense was 

therefore well-armed with information upon which to confront and cross-examine both Avi and 

Major Lior,” who testified under pseudonym). The Court concluded that it could. Here, as in 

Ramos-Cruz and the other Fourth Circuit cases, the government disclosed a summary of Juan 

Diaz’s qualifications and expert testimony to the Defendants pursuant to Fed. R. Crim. P. 

16(a)(1)(G). See Ramos-Cruz, 667 F.3d at 501 (noting that the government “disclosed the 

substance of the testimony the two witnesses in question would provide at trial”). Through the 

government’s steadfast reliance on the Maryland MS-13 cases, Defendants were on notice that 

this same Juan Diaz had testified several times in that district under the same pseudonym, and 

they could have procured transcripts of his testimony in those cases to prepare themselves. In 

addition, the government proffered that Mr. Diaz would testify generally at trial about his 

credentials and qualifications as an expert witness on MS-13 and would be subject to crossexamination about them.7

 Because the Defendants had access to Juan Diaz’s expert report, a 

 7 Mr. Diaz’s trial testimony bore the government’s proffer out precisely. Mr. Diaz testified and 

was subject to an extensive voir dire about his qualifications and knowledge base, all without 

revealing any personal identifying information. 
16

summary of his qualifications, and his prior testimony, they had access to almost the entire

universe of possible ammunition for cross-examination. See El-Mezain, 664 F.3d at 492–93 

(noting that defendants were able to demonstrate, inter alia, pseudonymous expert’s “lack of 

knowledge and familiarity with the subject matter” and bias). Additionally, as in the Maryland 

MS-13 cases, “Juan Diaz” was only offered to provide “background information about the 

internal working of MS-13 generally,” not to give factual testimony about any activities 

undertaken by these specific defendants.8

 Ramos-Cruz, 667 F.3d at 501 (emphasizing “the 

limited focus of the witnesses’ testimony”). That Juan Diaz would only provide background 

information on MS-13 is an important distinction between this case and Celis, in which the 

witnesses shielded by the protective order were “insider witnesses” who lived in Colombia and 

testified “about their own involvement with appellants and the FARC in drug trafficking.” Id. at 

830 n.5 & 833. The more general nature of his testimony and the Defendants’ ready access to 

impeachment material about that testimony distinguished these facts from, for example, a 

pseudonymous eyewitness whose background and expected testimony are a mystery to the 

accused. 

These factors show that, even without Mr. Diaz’s true identity, Defendants had an 

opportunity for effective cross-examination. See Van Arsdall, 475 U.S. at 679 (“[T]he 

Confrontation Clause guarantees an opportunity for effective cross-examination, not crossexamination that is effective in whatever way, and to whatever extent, the defense might wish.” 

(quoting Delaware v. Fensterer, 474 U.S. 15, 20 (1985))). Accordingly, “when . . . safety 

concerns are balanced against the defendants’ ability to conduct meaningful cross-examination, 

the scale tips in favor of maintaining the secrecy of the witnesses’ names.” See El-Mezain, 664 

 8 Again, the government was true to its word at trial. Mr. Diaz only gave general testimony 

about MS-13, never touching on the specific acts allegedly committed by these Defendants.
17

F.3d at 492; see also Roviaro, 363 U.S. at 62 (requiring the Court to “balance[e] the public 

interest in protecting the flow of information against the individual’s right to prepare his 

defense”). 

III. CONCLUSION

For the foregoing reasons, when the need to preserve the Defendants’ right to 

effective cross-examination was balanced with the genuine and continuing threat to the safety of 

Juan Diaz and his family, the Court found that Juan Diaz could testify as an expert witness on the 

structure and operations of MS-13 in El Salvador without disclosure of his true name or personal 

identifying information to the defense. The Court thus granted the Government’s Motion for 

Protective Order as to Proposed Expert Witness, Dkt. 114. 

DATE: June 28, 2013

 /s/ 

ROSEMARY M. COLLYER

United States District Judge