State v. Van Oostendorp, 397 P.3d 877

Defendant Trevor Van Oostendorp met the victim in 2013; the relationship became abusive, with physical violence, threats involving a gun, and controlling behavior.
Over Valentine’s weekend, defendant forced the victim into the shower, assaulted her (belt in mouth, urinated on her), and anally penetrated her; defendant admitted the act but disputed consent.
Defendant was charged with forcible sodomy (first-degree felony); trial centered on consent and defendant’s claimed reasonable mistake of fact about consent.
The prosecution relied heavily on prior-bad-acts evidence to show a pattern of domestic/sexual abuse to rebut defendant’s mistake-of-fact defense.
Trial court admitted much prior-act evidence, found the victim competent to testify despite some memory gaps, and modified (but did not give verbatim) defendant’s proposed mistake-of-fact jury instruction. Jury convicted; defendant appealed.

Issue	Plaintiff's Argument	Defendant's Argument	Held
Competency of victim to testify	Victim was competent; State relied on her testimony	Van Oostendorp: memory gaps made victim incompetent and testimony unreliable	Court: Victim met low competency standard (perception + recall); gaps went to credibility for jury, not competence — affirmed conviction
Sufficiency of evidence	State: evidence (victim testimony + corroboration) sufficient to prove nonconsent beyond reasonable doubt	Van Oostendorp: without victim testimony case fails	Court: viewing record in favor of verdict, evidence sufficient; competency ruling upheld
Admissibility of prior-bad-acts (Rule 404(b)/403)	State: prior acts admissible for non-character purposes (pattern, victim’s state of mind, rebut mistake defense)	Van Oostendorp: evidence was prejudicial propensity evidence and should be excluded	Court: trial court did not abuse discretion; evidence relevant to consent and rebuttal of mistake claim; probative value not substantially outweighed by prejudice
Jury instruction on mistake of fact	State: prosecution required to disprove honest, reasonable belief of consent; court’s added language adequate	Van Oostendorp: requested specific instruction was required and its omission prejudiced defense	Court: defendant failed to identify differences or show prejudice; added instruction (“honestly and reasonably believed”) adequately conveyed defense; no reversible error

State v. Hamilton, 827 P.2d 232 (Utah 1992) (standard for reviewing sufficiency of evidence)
State v. Calliham, 57 P.3d 220 (Utah 2002) (low bar for witness competency under Utah R. Evid. 601/602)
Ladd v. Bowers Trucking, Inc., 264 P.3d 752 (Utah Ct. App. 2011) (memory gap can show lack of capacity to observe/recall)
State v. Eldredge, 773 P.2d 29 (Utah 1989) (opportunity and capacity to perceive as foundation for testimony)
State v. Prater, 392 P.3d 398 (Utah 2017) (jury as exclusive judge of witness credibility; appellate review limited)
State v. Thornton, 391 P.3d 1016 (Utah 2017) (404(b) framework — admissibility for non-propensity purposes and 403 balancing)
State v. Lucero, 328 P.3d 841 (Utah 2014) (probative vs. prejudicial balancing for other-acts evidence)
State v. Marchet, 284 P.3d 668 (Utah Ct. App. 2012) (instruction language on honest and reasonable belief regarding consent)
State v. Stringham, 17 P.3d 1153 (Utah Ct. App. 2001) (standard for reversible error from refusal to give requested jury instructions)