Robin Williams died of hanging on Monday morning, Marin County sheriffs confirmed at a press conference on Tuesday.

Lieutenant Keith Boyd made the announcement outside of the Marin County Sheriffs Office in San Rafael, California, adding that Williams, 63, was suspended with a belt around his neck and found in a seated position.

The Oscar winner was clothed and rigor mortis had set in, and authorities noted that there were superficial wounds found on one of his wrists, indicating that the late actor may have tried to cut himself before the hanging. A pocket knife was also found nearby the scene of the death.

Williams was last seen alive by his wife, Susan Schneider, on Sunday night before she went to bed at their Northern California home. When she left the house on Monday morning around 10:30am, she apparently thought Williams was still asleep in a separate room, and it wasn't until over an hour later that Williams' assistant entered the room and discovered the body.

A toxicology report will be conducted, but will take two to six weeks to be completed.