C.R.S. § 18-1-407

(1) “Affirmative defense” means that unless the state’s evidence raises the issue involving the alleged defense, the defendant, to raise the issue, shall present some credible evidence on that issue. (2) If the issue involved in an affirmative defense is raised, then the guilt of the defendant must be established beyond a reasonable doubt as to that issue as well as all other elements of the offense.