People v. Day.

2026 CO 16. No. 24SC16. Mental-Condition Evidence—Mental-Condition Examination—Competency.

March 16, 2026

The supreme court held that a defendant must be competent before undergoing a mental-condition examination under CRS § 16-8-107(3)(b). Accordingly, a trial court shouldn’t use an incompetent defendant’s failure to cooperate with personnel during a competency evaluation as a basis to exclude expert mental-condition evidence at trial. Because the trial court did so here, the court affirmed the judgment of the court of appeals and remanded the case for a new trial on all charges for which Day’s culpability was at issue.

The court also provided guidance on how courts should apply People v. Moore, 2021 CO 26, 485 P.3d 1088, and CRE 403 in determining the admissibility of mental-condition evidence.