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MICHAEL BAILEY 

United States Attorney 

ANNA WRIGHT

Assistant U.S. Attorney 

NATHANIEL J. WALTERS 

Assistant U.S. Attorney 

State Bar No.: 029708 

405 West Congress, Suite 4800 

Tucson, Arizona 85701-5040 

Telephone: (520) 620-7300 

E-mail: anna.wright@usdoj.gov 

 nathaniel.walters@usdoj.gov 

Attorneys for Plaintiff 

IN THE UNITED STATES DISTRICT COURT 

FOR THE DISTRICT OF ARIZONA 

United States of America, 

 Plaintiff, 

 vs. 

Scott Daniel Warren, 

 Defendant.

18-CR-223-TUC-RCC (DTF) 

GOVERNMENT’S RESPONSE TO 

DEFENDANT’S MOTION IN LIMINE TO 

ADMIT EVIDENCE OF POSSIBLE BIAS 

OR PREJUDICE AFFECTING 

GOVERNMENT WITNESSES

The United States of America, by and through its undersigned attorneys, hereby 

responds to the defendant’s Motion in Limine to Admit Evidence of Possible Bias or 

Prejudice Affecting Government Witnesses. Doc. 320. For the reasons discussed below, 

the government respectfully requests that the Court deny the defendant’s motion in its 

entirety. In the alternative, the government respectfully asks that the Court limit the crossexamination and allow the government an opportunity to rebut any inference of bias. 

I. Legal Summary 

Evidence of a witness’ potential bias is relevant impeachment evidence that may be 

explored on cross-examination. United States v. Abel, 469 U.S. 45, 50-51 (1984); United 

States v. Hankey, 203 F.3d 1160, 1171 (9th Cir. 2000). “Cross-examination for bias or 

prejudice is generally required only to the extent of exploring the subject with the witness, 

first in a preliminary way to determine if further inquiry is justified, and then more 

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extensively of the witness’ responses or attitude appear to justify it.” Chipman v. Mercer, 

628 F.2d 528, 532-33 (9th Cir. 1980). 

Bias is a term used...to describe the relationship between a party and 

a witness which might lead the witness to slant, unconsciously or 

otherwise, his testimony in favor of or against a party. Bias may be 

induced by a witness’ like, dislike, or fear of a party, or by the witness’ 

self-interest. 

Abel, 469 U.S. at 52. Bias may be directed personally at a defendant or towards a 

group a defendant belongs to. Chipman, 628 F.2d at 532; see also United States v. Kartman, 

417 F2d 893, 897 (9th Cir. 1969). 

However, such evidence of bias is not automatically admissible, and a trial court 

retains significant latitude in setting limits on cross-examination. Delaware v. Van Arsdall, 

475 U.S. 673, 679 (1986). A trial court may limit such cross-examination if its probative 

value is outweighed by undue prejudice, including the dangers of harassment, confusion of 

the issues, the witness’ safety, or questioning that is repetitive or only marginally relevant. 

Van Arsdall, 475 U.S. at 679; see also Abel, 469 U.S. at 470; United States v. Beardslee, 

197 F.3d 378, 384 (9th Cir. 1999); United States v. James, 139 F.3d 709, 713 (9th Cir. 

1998). Consistent with the Confrontation Clause, a trial court may limit cross-examination 

regarding a witness’ potential bias so long as the jury has “has sufficient information to 

assess the credibility of the witness.” United States v. Larson, 495 F.3d 1094, 1103 (9th 

Cir. 2007). A trial court may also entirely preclude an area of cross-examination where the 

link between the proffered evidence and any inference of bias is remote or speculative. 

James, 139 F.3d at 713; see also United States v. McClintock, 748 F.2d 1278, 1289-90 (9th 

Cir. 1984); United States v. Marshall, 526 F.2d 1349, 1361 (9th Cir. 1975). 

Finally, a party may offer extrinsic evidence of a witness’s bias, and, if a witness is 

impeached with extrinsic evidence, the party proffering the witness may offer evidence to 

rebut the inference of bias. Abel, 469 U.S. at 468; James, 139 F.3d at 713. A trial court 

may take the distraction of proving up and rebutting these collateral matters into account 

in determining whether and to what extent to allow cross-examination regarding a witness’

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potential bias. Lewy v. Southern Pacific Trans. Co., 799 F.2d 1281, 1298-99 (9th Cir. 

1986); Marshall, 526 F.2d at 1361. 

II. Discussion 

a. Prior Investigation of Illegal Activity at the Barn 

Prior to the first trial in this matter, the government disclosed materials related to 

Border Patrol Agent (BPA) Marquez’s prior investigation of illegal activity occurring at or 

near the Barn, including reports, text messages, and other materials. This evidence showed 

that, prior to setting up surveillance at the Barn on January 17, 2018, BPA Marquez had 

information that neighbors of the Barn found items associated with illegal alien traffic, 

including carpet booties and black water jugs, near the Barn, and saw illegal aliens walking 

in the area. (TR 5/30/19 at 28:12-13). 

At trial, the defendant objected to admission of this evidence and argued that the 

government should not be allowed to introduce any of this evidence because it was 

anonymous, rank hearsay, (TR 5/29/19 at 58:15-59:7), and created a “significant 

Confrontation Clause problem.” (TR 5/30/19 at 30:22-31:2). The Court precluded the 

government from eliciting testimony about this topic, but, after the defendant opened the 

door on cross-examination, allowed the government to ask BPA Marquez limited questions 

about this topic. (TR 5/30/19 at 32:14-18). 

The defendant now argues that he should be allowed to cross-examine BPA 

Marquez regarding certain text conversations and portions of his initial report related to 

this prior investigation because they show that BPA Marquez had an impermissible bias 

that would lead him to exaggerate his observations of the events of January 17, 2018. Doc. 

320 at 12-14. However, the documents relied on by the defendant do not support any 

inference of bias. Beginning with BPA Marquez’s initial report, it references the 

defendant’s work with NMD, including his public speaking on immigration issues, in the 

context of ongoing suspicions that NMD was involved in illegal activity. Doc. 313-1. The 

report does not characterize or improperly focus on the defendant’s views on immigration. 

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Turning to the first text conversation, it involves a United States Fish and Wildlife 

(USFWS) employee sending BPA Marquez information about individuals other than the 

defendant believed to be associated with No More Deaths who applied for permits at the 

Cabeza Prieta National Wildlife Refuge (CPNWR) and informing BPA Marquez that the 

defendant will be charged regarding violations of the CPNWR regulations. Doc. 313-2 at 

2-9. In response to the text about potential charges against the defendant, BPA Marquez 

responds, “Yeah I heard about Scott Warren too I think.” Id. at 6. Nothing about this text 

conversation suggests that BPA Marquez is improperly targeting NMD or the defendant. 

The second text conversation is even more innocuous. In that conversation, among 

other things, BPA Marquez provided the defendant’s address to a USFWS employee for 

the purpose of serving the summons in the misdemeanor matter. Doc. 313-2 at 11-18. There 

is nothing in the text conversation to suggest that BPA Marquez or anyone else is 

attempting to “track” the defendant. See Doc. 320 at 14. 

As discussed above, there is nothing in BPA Marquez’s initial report or text 

conversations to suggest that he was biased such that he would exaggerate his observations 

of the events of January 17, 2018. To the extent that these items are even marginally 

relevant to the issue of bias, there limited probative value is outweighed by the danger of 

confusing the issues. See Fed. R. Evid. 403. In addition, if the defendant is permitted to 

cross-examine BPA Marquez about these items, then the government will be entitled to 

introduce the other information that BPA Marquez found as a result of his prior 

investigation, including the carpet booties and black water jugs, to rebut any inference of 

bias. 

b. Border Patrol Text Message 

The defendant also seeks to cross-examine Border Patrol “agents about their 

participation in” a group text conversation on January 17, 2018. Doc. 320 at 14. This text 

conversation involved various agents coordinating surveillance and the knock-and-talk on 

that day. Doc. 186, Exhibit 10. The government agrees that the defendant may crossexamine agents as to any bias based on their own text messages in this conversation. 

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However, any cross-examination regarding potential bias should not be based on text 

messages sent by other agents. See Jencks Act (18 U.S.C. § 3500). In addition, admission 

of the text conversation itself into evidence would confuse the issues and cause undue 

prejudice by placing irrelevant information and out-of-context hearsay statements in front 

of the jury. See Doc. 320 at 14; see also Fed. R. Evid. 403. 

c. No More Deaths Public Relations Campaign 

The defendant also seeks to cross-examine BPAs Marquez and Burns about a press 

release sent by NMD on the morning of January 17, 2018. Doc. 320 at 15. The defendant 

has failed to produce any evidence that either agent knew about the press release or 

accompanying report prior to setting up surveillance. The text messages and emails 

disclosed by the government show that the agents did not receive a copy of the press release 

or report at any point during January 17, and that BPA Marquez became aware of the press 

release only after making arrangements to surveil the Barn. See Doc. 186 at Exhibits 8-9.

Despite this evidence, the defendant now speculates that the agents heard about the press 

release and report at muster, see Doc. 320 at 16, but provides no evidence or argument as 

to why these items would merit mention at muster. The defendant also argues that the press 

release and report could still support an inference of bias if the agents learned about the 

press release and report prior to their testimony. Doc. 320 at 15. This is pure speculation.

Nothing in Border Patrol’s response to the press release and report suggests that any agent 

would bear such a grudge as to commit perjury or fabricate evidence. Accordingly, the 

press release and report are not relevant to the issue of bias, since any inference of bias 

would be based on speculation and contrary to the evidence. See James, 139 F.3d at 713; 

see also McClintock, 748 F.2d at 1289-90; Marshall, 526 F.2d at 1361. 

Even if the press release and report are marginally relevant to the issue of bias, the 

defendant’s cross-examination on this issue should be limited to asking the agents whether 

they have ever reviewed the press release and/or report, and, if so, whether it has had any 

impact on their testimony in this case. See Chipman at 532-33. This line of questioning 

should not be used to get into the particulars of the report, including its allegations and 

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findings, or to admit the report into evidence. Doing so would confuse the issues by 

allowing the defendant to use the trial as a platform for debating immigration policy. See

https://calendar.hope.edu/event/border program studies info session#.XYlBY8tYaP4

(accessed September 23, 2019) (“Scott and No More Deaths want to use the trial to visiblize

[sic] the crisis happening in this area of Arizona...”); see also Fed. R. Evid. 403. Doing so 

would also generate a side-show related to the methodology of the report and the soundness 

of its conclusions. 

d. Evidence of Intent 

Finally, much of the defendant’s arguments as to the impeachment value of this 

evidence rests on the premise that the government’s case as to his intent is weak and comes 

down to a “credibility contest[.]” Doc. 320 at 10. This is not accurate. Throughout this case, 

BPAs Burns and Marquez have testified consistently with their reports regarding their 

observations of the defendant and the two illegal aliens on January 17, 2018. In addition, 

one of the illegal aliens initially admitted that the defendant gave him directions further

north, although he recanted this statement during the video depositions, and the defendant 

admitted that he told the aliens where it was safe to walk and how to navigate using the 

nearby mountains. See TR 6/6/19 at 62-63 (“I told them that the critical piece of 

information they need to know is that Highway 85 runs between those two mountains. If 

you are in the desert and you are lost or you have some kind of injury, you have Childs 

Mountain here, Hat Mountain here, the highway runs between those two. It’s absolutely 

essential, if you’re going to self-rescue, that you walk this way...and you don't walk that 

way...”). It is also uncontested that the two illegal aliens stayed at the Barn for four days, 

that they were not in danger of death or injury at any point during their stay, and that the 

defendant gave them permission to stay and provided them with everything necessary for 

their stay. 

III. Conclusion 

For the reasons discussed above, the government respectfully requests that the Court 

deny the defendant’s motion in its entirety. In the alternative, if the Court allows the 

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defendant to cross-examine regarding the prior investigation, the text conversations, or 

NMD’s press release and report, the government respectfully asks that the Court limit the 

cross-examination and allow the government an opportunity to rebut any inference of bias.

 Respectfully submitted this 25th day of September, 2019. 

 MICHAEL BAILEY 

United States Attorney 

District of Arizona 

 /s/ Anna R. Wright & Nathaniel J. Walters

 ANNA WRIGHT &

 NATHANIEL J. WALTERS 

 Assistant U.S. Attorneys 

Copy of the foregoing served electronically or by 

other means this 25th day of September, 2019, to: 

All ECF participants 

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