MARIN COUNTY, Calif. (KABC) -- Actor-comedian Robin Williams was found dead at his Tiburon home Monday morning in an apparent suicide by asphyxiation, Marin County Sheriff's officials said.The Marin County Sheriff's Department received a 911 report of a male not breathing in a residence in unincorporated Tiburon, California at 11:55 a.m. Monday. Emergency personnel arrived and pronounced the subject deceased at 12:02 p.m. He was identified as Robin McLaurin Williams, 63.Williams was last seen alive at the residence at approximately 10 p.m. Sunday, investigators said. His wife also lives at the residence."This morning, I lost my husband and my best friend, while the world lost one of its most beloved artists and beautiful human beings. I am utterly heartbroken. On behalf of Robin's family, we are asking for privacy during our time of profound grief. As he is remembered, it is our hope the focus will not be on Robin's death, but on the countless moments of joy and laughter he gave to millions," Susan Schneider, Williams' wife, said Monday. A representative said Williams had been battling severe depression lately.Just last month, Williams announced he was returning to a 12-step treatment program he said he needed after 18 months of nonstop work. He had sought treatment in 2006 after a relapse following 20 years of sobriety.The Marin County Sheriff's Department said a forensic examination was scheduled for Tuesday, including toxicology testing.News of Williams' death quickly spread across social media, with celebrities, co-stars and everyday people expressing shock, disbelief and appreciation for his career.His daughter Zelda Williams tweeted, "I love you. I miss you. I'll try to keep looking up."From his breakthrough in the late 1970s as the alien in the hit TV show "Mork and Mindy," through his standup act and such films as "Good Morning, Vietnam," the short, barrel-chested Williams ranted and shouted as if just sprung from solitary confinement. He was a riot in drag in "Mrs. Doubtfire," or as a cartoon genie in "Aladdin."He won his Academy Award in a rare, but equally intense dramatic role, as a teacher in the 1997 film "Good Will Hunting." He also played for tears in "Awakenings," "Dead Poets Society" and "What Dreams May Come." Williams won three Golden Globes, for "Good Morning, Vietnam," ''Mrs. Doubtfire" and "The Fisher King." Williams had recently wrapped production in the upcoming movie "Night at the Museum: Secret of the Tomb." In April, Fox 2000 said it was developing a sequel to "Mrs. Doubtfire" and Williams was in talks to join the production.Williams married graphic designer Susan Schneider on October 22, 2011, in Napa Valley. The couple met in 2009, shortly before Williams underwent heart surgery. It was his third marriage. The actor has three children from previous marriages.