State v. Richard L. Pringle, 2020AP6-CR, 11/17/20, District 3 (not recommended for publication); case activity (including briefs) No witness, expert or otherwise, may give an opinion that a mentally competent witness is telling the truth. State v. Haseltine, 120 Wis. 2d 92, 352 N.W.2d 673 (Ct. App. 1984).  This case, which the court of appeals […]