COLUMBIA, S.C. - Authorities say a man who was found incompetent to stand trial in the March 2006 deaths of his mother and stepfather has escaped from a Columbia mental hospital.

Oconee County deputies said 35-year-old Jason Carter left the hospital Thursday and might be in a stolen 1991, white, Chevrolet van.

The Department of Mental Health says someone left the G. Werber Bryan Psychiatric Hospital without permission, but medical privacy laws won't allow the agency to release the escapee's name.

Agency spokesman Mark Binkley says the escaped patient was working at a supply business on the hospital's campus. He says an investigation is underway to determine how the involuntarily committed patient got away.

Authorities say Carter shot his mother and stepfather at their Seneca home, then wrapped their bodies in plastic.