Prominent L.A. attorney Barry Levin, 54, who helped defend Erik Menendez in his murder case and who more recently took on actor Robert Blake as a client, died of a self-inflicted gunshot wound to the head, an autopsy showed Sunday. On Saturday afternoon, the lawyer, reportedly upset over a debilitating illness, was found slumped over the steering wheel of his car, which was parked at a veterans’ cemetery. (Levin had been a paratrooper in Vietnam.) The autopsy confirmed preliminary findings that Levin had taken his own life, said L.A. County Coroner’s Lt. Fred Corral. Levin’s brother-in-law and law partner, Ron Dorfman, told reporters that Levin suffered from Gaucher’s disease, a genetic enzyme-deficiency disorder that causes victims to bleed and bruise easily. The condition left him in constant pain. Levin was the second attorney hired by the former “Baretta” star, 67, to represent him in the still-unsolved case of his wife’s May 4 murder. Blake’s main attorney has been Harland Braun.