(Hollywood Reporter) -- Robin Williams committed suicide by hanging himself with a belt, Marin County police said at a Tuesday press conference.
The preliminary cause of death is suicide due to asphyxia, Lt.Keith Boyd told the media.
According to Boyd, Williams' assistant found him hanging in a bedroom, slightly suspended in a seated position, with superficial cut marks on the inside of his left wrist; rigor mortis had already set in. He was pronounced dead at 12:02 p.m. on Monday.
Williams was last seen alive by his wife at approximately 10:30p.m. on Sunday, Boyd added, before she went to bed.
Around 10:30 a.m. the next morning, Williams' wife left the house, believing Williams to still be asleep, but his assistant grew concerned around 11:45 a.m. when Williams did not respond to repeated knocks on his bedroom door, Boyd relayed. Upon gaining entrance to the bedroom, the assistant found Williams clothed, hanging against a closed closet door, with a belt secured around his neck, and the other end of the belt wedged between the door and the door frame, Boyd explained.
With respect to the cut marks on his wrist, Boyd noted that a pocket knife with dried red material that appeared consistent with dried blood on it was found near Williams' body. It's unknown if the substance is blood or if that blood belonged to Williams, Boyd pointed out.
An autopsy was conducted on Tuesday morning in Napa County. Boyd declined to reveal whether a note had been left at the scene.
Boyd did note, in recounting the 911 call received after Williams was found, that the caller sounded distraught.