Clarifying Trial Discretion and Warrant Particularity: Expert Witness Designation and Vehicle Search in Marquez v. Wyoming

Introduction

This commentary examines the Supreme Court of Wyoming’s decision in Justin Armando Marquez v. The State of Wyoming (2025 WY 61), rendered on May 30, 2025, which affirmed the conviction of Mr. Marquez for second-degree murder and rejected his appeals relating to:

The district court’s denial of his eleventh-hour motion to designate an expert witness;
The rejection of two motions to suppress evidence seized from his vehicle;
A Franks-type challenge to the search warrant affidavits.

The underlying homicide investigation began when Ryan Schroeder disappeared in June 2021. Cell-phone records, witness testimony and forensic evidence led investigators to Mr. Marquez’s maroon Hyundai SUV, where decomposition odors and bloodstains were found. Mr. Marquez was tried in Natrona County District Court, convicted by a jury, sentenced to 70 years to life, and timely appealed. The Supreme Court of Wyoming consolidated his three appellate issues into two questions:

Did the district court abuse its discretion by denying a late expert-witness designation?
Did the district court err in denying suppression of vehicle search evidence?

Summary of the Judgment

In a unanimous opinion authored by Justice Jarosh, the Court:

Expert Witness Designation: Held the district court did not abuse its discretion under the Sixth Amendment’s Compulsory Process Clause or Wyoming law when it refused to entertain Mr. Marquez’s motion to designate an expert less than a week before trial, given (a) the delay was attributable to defense conduct, (b) the State would be prejudiced, and (c) self-defense testimony could be pursued through other means;
Scope of Vehicle Search Warrant: Found that, despite two mis-checked boxes indicating “on the premises” rather than “in the vehicle,” the warrant caption, incorporated affidavits and detective testimony “virtually eliminated” any possibility of searching the wrong place. The warrant sufficiently described the 2008 maroon Hyundai by registration number, VIN and storage-lot address;
Franks Hearing Challenge: Concluded Mr. Marquez failed to prove Detective Patrick knowingly or recklessly (a) included a speculative reference to cleaning agents or (b) omitted benign statements from his sister. Even setting aside those passages, probable cause remained.

The Supreme Court therefore affirmed the district court’s rulings in all respects.

Analysis

1. Precedents Cited

Taylor v. Illinois, 484 U.S. 400 (1988): Balancing the defendant’s compulsory process right against public interests and adversarial integrity.
Lawson v. State, 994 P.2d 943 (Wyo. 2000): Exclusion of untimely witness designations absent valid excuse is an abuse of discretion only when fairness and reliability suffer.
Gruwell v. State, 2011 WY 67, 254 P.3d 223: Expert-witness exclusion upheld where defense waited until three business days before trial.
Franks v. Delaware, 438 U.S. 154 (1978): Requirements for a hearing when an affidavit allegedly contains intentional or reckless falsehoods.
Herdt v. State, 2023 WY 42, 528 P.3d 862: Two-pronged test for warrant particularity; practical accuracy over technicality.
Garcia v. State, 2025 WY 17, 563 P.3d 484: Affirms presumption of warrant validity and total-document reading when incorporated by reference.

These cases guided the Court’s evaluation of (1) the timeliness and substance of expert disclosures, (2) the “particularity” requirement of the Fourth Amendment, and (3) the high bar for Franks challenges.

2. Legal Reasoning

Expert Witness Designation:

The Sixth Amendment and Article 1, § 10 (Wyoming Constitution) guarantee compulsory process but allow reasonable regulation. Taylor’s factors emphasize: reliability of evidence, fair administration of justice, and prejudice to the truth-finding process.
Scheduling orders carry weight. Mr. Marquez missed the November 5, 2023 expert-designation deadline and waited until February 20, 2024—six days before trial—to seek a self-defense expert. He argued new disclosures from the defendant justified “good cause.”
The district court reasonably found the delays self-inflicted, the proposed summary insufficient, the State prejudiced (no time for rebuttal), and self-defense could be presented through testimony, cross-examination, counsel argument and jury instructions.
This analysis parallels Gruwell, ¶ 17, 254 P.3d at 229: a last-minute expert harms adversarial integrity.

Scope of Vehicle Search Warrant:

Fourth Amendment particularity: warrants must describe “the place to be searched” with enough detail to prevent exploratory “general searches.” Herdt’s two-pronged test asks:
1. Could the officer locate the subject with reasonable effort?
2. Is there a risk of searching the wrong premises?
Here, the caption named “2008 Maroon Hyundai,” gave registration and VIN, and the affidavit explicitly sought a search “in the vehicle” parked at Schmitt Storage. Although two check-boxes were mis-marked, the warrant incorporated the affidavit by reference, eliminating any ambiguity. Practical accuracy prevailed.

Franks Hearing Challenge:

To trigger a Franks hearing, the defendant must make a substantial preliminary showing that:
1. A false statement was made knowingly or with reckless disregard for the truth;
2. The allegedly false statement was material to probable cause; and
3. Setting aside the falsehood, the affidavit lacks probable cause.
Mr. Marquez claimed Detective Patrick’s affidavit improperly:
- Included a generalized reference to finding “cleaning agents” to remove blood;
- Omitted benign material from his sister about normal car-storage practices.
The district court credited the detective’s testimony that (a) law enforcement training and the circumstances supported the cleaning-agent reference, and (b) she did not deem the sister’s background details relevant to probable cause. There was no evidence of deliberate falsehood or reckless omission, and probable cause remained strong.

3. Impact on Future Practice

Defense counsel must heed scheduling orders on expert designations and cannot rely on late strategic disclosures to secure continuances or surprise expert testimony.
Courts will construe warrants practically, reading captions and incorporated affidavits together to uphold searches when the subject is clearly described, even if form-entry checkboxes contain minor errors.
Franks challenges require proof of intentional or reckless misrepresentation or omission—mere negligence or generalizations will not suffice.

Complex Concepts Simplified

Compulsory Process Clause: A defendant’s right to call witnesses, subject to reasonable court rules.
Taylor Factors: A balancing test weighing fairness, reliability of evidence, and prejudice when excluding witnesses.
Scheduling Order: A court timetable that fixes deadlines for expert disclosures; missing them demands a good-cause showing.
Warrant Particularity: The Fourth Amendment requires warrants to specify exactly where and what can be searched; small drafting mistakes can be cured by reading the entire warrant and attached affidavit.
Franks Hearing: A mini-trial on whether the officer deliberately or recklessly lied or omitted facts in the affidavit; if proven and material, the entire search is invalidated.

Conclusion

Marquez v. Wyoming reaffirms that trial courts have broad discretion to manage expert-witness deadlines and to interpret search warrants with a commonsense approach. It emphasizes counsel’s duty to comply with scheduling orders and to develop trial strategies promptly. It also clarifies that inadvertent affidavit generalities or omissions, without proof of reckless intent or material prejudice, will not undo a warrant supported by ample probable cause. This decision thus provides crucial guidance for criminal defense and prosecution practices in Wyoming.