The man identified by California law enforcement officials as the gunman in a mass shooting at a San Jose rail yard on Wednesday lived alone and had a hostile personality, according to interviews with a neighbor and an ex-girlfriend, as well as a review of court records. The gunman, Samuel James Cassidy, 57, lived southeast of downtown San Jose, in a suburban neighborhood of cul-de-sacs and palm trees, public records show. Doug Suh, a real estate agent who lived across the street, described Cassidy, who authorities say appeared to have killed himself, as someone with a short temper.