Garrison v. State, 409 P.3d 1209

Mark Garrison was convicted of first‑degree arson for burning his estranged wife's mobile home; prosecution alleged gasoline was used and a late‑1990s Dodge Ram was seen near the scene.
The State gave pretrial notice under W.R.E. 404(b) of ten prior/other‑acts incidents (threats, property destruction, physical/sexual assaults, and multiple violations of a protective order).
At a pretrial hearing the court excluded some incidents/portions but admitted others as relevant to relationship, intent, motive, identity, and malice; the court said it would provide a fuller Gleason analysis if the case went to trial.
During opening, defense counsel “opened the door” by suggesting the complainant exaggerated previously excluded incidents; the prosecutor then elicited testimony about those incidents.
The district court did not place a full articulated Gleason (404(b)) analysis on the record until after the close of evidence; no limiting instruction was requested or given.
On appeal Garrison argued (1) plain error because the Gleason analysis occurred after admission of evidence, and (2) the court abused its discretion in admitting the other‑acts evidence. The Wyoming Supreme Court affirmed.

Issue	Plaintiff's Argument	Defendant's Argument	Held
Timing of Gleason/404(b) analysis	Court violated Gleason by issuing its full analysis only after evidence was admitted, producing plain error	Trial court can satisfy Gleason later; no contemporaneous objection was made	No plain error; Gleason prefers pretrial rulings but timing requirement is not absolute; court holds Gleason analysis must at minimum be contemporaneous with admissibility ruling going forward
Admissibility of other‑acts evidence (pre‑fire incidents)	Prior acts were unfairly prejudicial and not necessary because separation and protective order were undisputed	Prior acts formed the course of conduct, relevant to identity, motive, intent, and provided context	No abuse of discretion; pre‑fire incidents admissible as course of conduct probative of identity and motive and not substantially more prejudicial under Rule 403
Admissibility of other‑acts evidence (post‑fire phone calls)	Less relevant and more prejudicial; should be excluded	Phone calls illustrated continuing relationship and were probative of context and identity	No abuse of discretion; post‑fire calls admissible and not extremely inflammatory
Admission of incidents defense “opened the door” to	Defense argues reopening excluded matters was improper	State contends defense opened the door in opening statement	Correct to admit those matters after defense opened the door; they were no longer barred

Gleason v. State, 57 P.3d 332 (Wyo. 2002) (establishes factors/procedure for 404(b) analysis)
Vigil v. State, 224 P.3d 31 (Wyo. 2010) (reiterates preference for pretrial 404(b) rulings; addresses timing and prejudice)
Hodge v. State, 355 P.3d 368 (Wyo. 2015) (treats pretrial 404(b) demand as a timely objection for review)
Williams v. State, 99 P.3d 432 (Wyo. 2004) (discusses timing and rationale for 404(b) analysis)
Rolle v. State, 236 P.3d 259 (Wyo. 2010) (appellate standard: review trial court for abuse of discretion on 404(b))
Bromley v. State, 150 P.3d 1202 (Wyo. 2007) (explains abuse‑of‑discretion limits and course‑of‑conduct rationale)
Law v. State, 98 P.3d 181 (Wyo. 2004) (Rule 403 undue prejudice standard)
Proffit v. State, 191 P.3d 963 (Wyo. 2008) (clarifies Rule 403 reversible‑error standard)