A judge has ruled that a University of Southern California graduate student was insane when he stabbed to death a professor on campus.
Tuesday's ruling means that 29-year-old David Brown could spend the rest of his life in a state mental hospital.
Brown had pleaded not guilty and not guilty by reason of insanity but withdrew the not-guilty plea.
Brown killed his mentor, 50-year-old Bosco Tjan, in December 2016 in a lab that the psychology professor ran.
Prosecutors say Brown told authorities he believed he was "a victim of human experimentation."
City News Service says Tjan's widow told the court that she feels helpless when her son asks why the professor was killed. Carissa Pang says she told her son that the killer was "mentally sick and having bad thoughts."