USA v. Walker

IN THE UNITED STATES DISTRICT COURT
FOR THE DISTRICT OF KANSAS
UNITED STATES OF AMERICA, 	)
)
Plaintiff, 	)
)
v. 	) 	Case No. 25-MJ-90005-BGS
)
ANTONIO LAMAR WALKER, JR., 	)
)
Defendant. 	)
ORDER
Before the Court is the Government's Motion for Reciprocal and Specific Discovery
pursuant to Federal Rule of Criminal Procedure 16(b), seeking clarification regarding relevant
scientific literature materials relied upon by Defendant's expert witness.1 (Doc. 18). Defendant
opposes the motion, contending that the requested materials are not within Defendant’s possession,
custody, and control, and that they are generally publicly available, and therefore not subject to
production under Rule 16. Having considered the parties' submissions and the applicable law, the
Court GRANTS the motion.
BACKGROUND
On October 10, 2025, Defense filed a Notice of Expert Testimony (Doc. 17) designating
Aaron Olson, a forensic toxicology consultant, as an expert. A report, CV, and list of prior
testimony was contemporaneously sent to the Government. At the outset, the report states that Mr.
Olson indicates he relied upon “relevant scientific literature” (amongst other items) in forming his
opinions. The report spans seven pages – 3.5 pages that contain his analysis and opinions and 3.5
pages that set forth a list of 45 “References.” See Doc. 26-1.
1 The motion also seeks disclosure of Defendant’s medical records; however, those records were produced by the
Defendant and are no longer at issue.
Case B:25-po-90005-BGS Document 27 Filed 12/11/25 Page 1 of 3

Defendant asserts that the “remaining issue is whether Mr. Walker must produce physical
copies of that literature for the government” and that Rule 16 does not require defendants to
compile and produce publicly available materials. However, the Government clarifies in its Reply
that it is not seeking physical copies but instead seeks clarification of which of the 45 listed materials
were relied upon by the expert in forming his opinion. Defendant does not address this issue in his
briefing.
ANALYSIS
Federal Rule of Criminal Procedure 16(b)(1)(C)(iii) provides that the disclosure for each
expert witness must contain: a complete statement of the expert’s opinions, the bases and reasons
for those opinions, the witness’s qualifications, and a list of prior testimony.
Defendant’s expert report indicates that Mr. Olson relied upon “relevant scientific literature”
and then he lists 45 separate publications, treatises, and other materials, in support thereof.
However, the expert opinions span only 3.5 pages and within the opinion itself, it is not clear what
scientific literature cited by the expert was relied upon in formulating the opinions.
Under Rule 16, Defendant is required to provide the “bases and reasons” for the expert’s
opinions. A list of 45 references accompanying a 3.5-page expert report does not meaningfully
satisfy this requirement. It is implausible that an expert genuinely relied on 45 separate sources to
formulate the opinions contained in such a concise report. Without knowing which of the
referenced materials informed the expert’s analysis, the Government cannot adequately prepare for
trial. See United States v. Briscoe, 703 F. Supp. 3d 1288, 1294 (D.N.M. 2023) (the disclosure must
allow the opposition the ability to prepare for cross-examination and rebuttal).
For the foregoing reasons, the Government’s motion is GRANTED. By December 19,
2025, the Defendant shall supplement its expert report clarifying which of the 45 listed materials
comprise the “relevant scientific literature” that the expert relied upon in formulating his opinions.
Case B:25-po-90005-BGS Document 27 Filed 12/11/25 Page 2 of 3

The Government’s expert witness disclosure deadline is reset for January 9, 2026. Trial remains as
scheduled.
IT IS THEREFORE ORDERED that the Government’s motion (Doc. 18) is
GRANTED.
IT IS SO ORDERED.
Dated December 11, 2025, at Wichita, Kansas.
/s/ Brooks G. Severson
Brooks G. Severson
United States Magistrate Judge
Case B:25-po-90005-BGS Document 27 Filed 12/11/25 Page 3 of 3