Mr. Xaver lived in Sebring but had spent most of his life in Plymouth, Ind., a town about 23 miles south of South Bend, Ind., according to a friend of his, Nathaniel Heitkamp. Mr. Xaver had recently trained to be a correctional officer at Avon Park Correctional Institution, a prison about 20 miles north of Sebring, said Patrick Manderfield, a spokesman for the Florida Department of Corrections.
Mr. Heitkamp said he met Mr. Xaver about five years ago, when they were both teenagers and patients at Michiana Behavioral Health in Plymouth. A representative at Universal Health Services, the company that operates the center, did not immediately respond to a request for comment on Thursday.
Over the years, Mr. Xaver complained about being bullied at school and disliked by his family, said Mr. Heitkamp, who now works in the service industry.
When Mr. Xaver got upset, Mr. Heitkamp said, he openly talked about a desire to hurt people and how he had access to guns.