Can witness plea deals make testimony inherently improbable? State v. Prater Explained

In State v. Prater, the Utah Supreme Court addressed whether witness testimony becomes inherently improbable when witnesses receive plea deals and their trial testimony contradicts earlier statements to police. The court’s analysis provides important guidance on the limits of appellate review of jury credibility determinations.

Background and Facts

Anthony Prater was convicted of aggravated murder for shooting Vincent Samora, who was scheduled to testify against Prater’s associate in an upcoming trial. Three key witnesses—Ryan Sheppard, Donna Quintana, and Sherilyn Valdez—initially lied to police about the shooting but later testified at trial that Prater committed the murder. Each witness received favorable treatment: Sheppard and Quintana received reduced charges in exchange for testimony, while Valdez faced no charges. Additional evidence included a letter Prater wrote describing the shooting, forensic evidence indicating the passenger fired the shots, and testimony from another inmate that Prater confessed to the crime.

Key Legal Issues

Prater argued the witnesses’ testimony was inherently improbable because they materially changed their statements only after receiving favorable treatment from prosecutors. He claimed this rendered the evidence insufficient to support his convictions, asking the court to apply plain error review since he failed to preserve this challenge at trial.

Court’s Analysis and Holding

The court distinguished this case from State v. Robbins, where a child witness’s testimony was found inherently improbable. In Robbins, the witness made patently false statements to cover inconsistencies, and no corroborating evidence existed. Here, while the witnesses initially lied, their explanations for the lies (fear of retaliation, threats from police) did not “run so counter to human experience” as to render their testimony inherently improbable. The court emphasized that plea deals alone do not make testimony apparently false—such agreements affect credibility, which is exclusively for the jury to determine.

Practice Implications

This decision reinforces that appellate courts rarely second-guess jury credibility determinations. Attorneys challenging witness credibility must identify truly extraordinary circumstances beyond typical inconsistencies or prosecutorial incentives. The court’s analysis also demonstrates the importance of marshaling all supporting evidence when challenging sufficiency—Prater’s failure to address corroborating evidence significantly weakened his appeal.