(CNN) -- Actor Robin Williams was cremated and his ashes were scattered in San Francisco Bay, according to his death certificate.
Williams was found dead in his Northern California home August 11 from what investigators suspect was a suicide by hanging. The certificate, obtained by CNN on Thursday, says his ashes were scattered off the coast one day later.
It also says the cause of death is "pending investigation."
According to Marin County Assistant Deputy Chief Coroner Lt. Keith Boyd, investigators believe Williams used a belt to hang himself from a bedroom door.
Boyd would not confirm or deny whether Williams left behind a letter, saying that investigators would discuss "the note or a note" later.
The coroner's investigation "revealed he had been seeking treatment for depression," Boyd said.
He spent time in a treatment facility in July, a time when his wife and representative have said he was battling depression.
Media reports at the time speculated that Williams had resumed drinking alcohol, but a statement from his wife appears to dispute those reports.
Williams was sober but struggling with depression, anxiety and the early stages of Parkinson's disease when he died, his widow said last week.
"Robin spent so much of his life helping others," she said. Whether he was entertaining millions on stage, film or television, our troops on the front lines, or comforting a sick child -- Robin wanted us to laugh and to feel less afraid."
CNN's Alan Duke contributed to this report.
™ & © 2014 Cable News Network, Inc., a Time Warner Company. All rights reserved.