[Warning: Potentially Triggering Content] New details are coming out about the tragic death of Katherine Short. As we reported, Martin Short's 42-year-old daughter died from a self-inflicted gunshot wound to the head at her home in Los Angeles on Monday night. Law enforcement sources now tell TMZ on Thursday that Katherine's friend called the police after the social worker hadn't "been heard from in 24 hours." Katherine was known to go away for a bit when she was struggling with her mental health, but something about her going MIA must have been odd and concerning to the pal this time.