(AP) — A psychiatric patient who killed his caseworker — and grazed his psychiatrist before the doctor pulled out his own weapon and fired back — has a lengthy history of gun arrests, violence and mental health problems, authorities said. Plotts by then had shot the caseworker in the face and fired several shots at Silverman, including one that grazed his temple and another that struck his thumb, he said. Police in Upper Darby, where Plotts lived, were aware of at least three mental health commitments — including once after he cut his wrists and once when he threatened suicide — but said such stays can last just one to three days. Whelan said Plotts had spent time in a mental health facility, but he did not discuss any potential diagnosis. Plotts also had at least four gun arrests, along with assault and drug charges, according to police and court records. Hospital policy bars anyone except on-duty law enforcement officers from carrying weapons on campus, said a Mercy Health System spokeswoman.