Veteran film and television comedic actor Robin Williams was found dead on Monday. He was 63.

The cause of death is believed to be suicide via asphyxiation, according to the coroner’s office in Tiburon, Calif. He was found in his home.

His publicist said the actor had been battling depression of late.

“This is a tragic and sudden loss,” his publicist Mara Buxbaum said in a statement. “The family respectfully asks for their privacy as they grieve during this very difficult time.”

Williams is best known for both comedic and dramatic roles in movies including “Good Will Hunting,” for which he won a Best Supporting Actor in 1997. In addition, he won several Emmys, Golden Globes.

Williams’ film career was bookended by TV roles including his breakout role on the ABC sitcom “Mork & Mindy” in 1978. He returned to TV on CBS last season, “The Crazy Ones.”

A suicide bag, also known as an exit bag, is a device consisting of a large plastic bag with a drawcord used to commit suicide. It is usually used in conjunction with an inert gas like helium or nitrogen, which prevents the panic, sense of suffocation and struggling during unconsciousness (the hypercapnic alarm response) usually caused by the deprivation of oxygen in the presence of carbon dioxide. This method also makes the direct cause of death difficult to trace if the bag and gas canister are removed before the death is reported. Right-to-die groups recommend this form of suicide as certain, fast, and painless, according to a 2007 study