Wyo. R. Crim. P. 12.3 (2026)

Rule 12.3. The court may for cause shown allow late filing of the notice or grant additional time to the parties to prepare for trial or make such other order as may be appropriate. (c) Mental examination of defendant. — Upon the entry of a plea of not guilty by reason of mental illness or deficiency under W.S. 7-11-301 et seq., the court shall order an examination as required by statute. No statement made by the defendant in the course of any examination or treatment and no information received by any person in the course thereof is admissible in evidence in any criminal proceeding on any issue other than that of the mental condition of the defendant except that if the defendant testifies, any statement made by the defendant in the course of examination or treatment pursuant to W.S. 7-11-301 et seq., may be admitted: (1) For impeachment purposes; or (2) As evidence in a criminal prosecution for perjury. (d) Failure to comply. — If there is a failure to give notice when required by subdivision (b) or to submit to an examination when ordered under subdivision (c), the court may exclude the testimony of any expert witness offered by the defendant on the issue of the defendant’s defense of mental illness or deficiency. (e) Inadmissibility of withdrawn plea or notice. — Evidence of a plea or notice given under subdivision (b), later withdrawn, is not, in any civil or criminal proceeding, admissible against the defendant. (f) Expansion of rights. — Nothing in this rule is intended to expand the

Rule 12.3 WYOMING COURT RULES 42

circumstances where a claim of mental illness or deficiency or any other mental condition may be raised.

Compare. — Rule 12.2, Fed. Rules Cr. Proc. teen Years,” see XXXIII Land and Water L. Rev.