Doc Refuses to Sign Shandling's Death Certificate The coroner's office has now launched an investigation into the cause of death By Michael Harthorne, Newser Staff Posted Mar 26, 2016 12:10 PM CDT 21 comments Comments Garry Shandling's doctor is refusing to sign his death certificate. (Photo by Rob Latour/Invision/AP, File) (Newser) – Legendary comedian Garry Shandling died Thursday morning, but his doctor has "repeatedly refused" to sign his death certificate, prompting an investigation by the Los Angeles County Coroner's Office, TMZ reports. The doctor hadn't seen Shandling in more than a year, believed him to be healthy, and can't figure out why he died. According to the New York Daily News, sources say Shandling died of a heart attack after experiencing aches and shortness of breath on Wednesday. “It’s a shock,” one source says. “He seemed pretty healthy, took care of himself. There were no known heart issues at all in his history.” The coroner's office will now have to determine Shandling's cause of death. It has subpoenaed his medical records and taken blood samples from the emergency room where the comedian was pronounced dead.