you laugh so hard your ribs hurt comedy specials. >> oh! yea! >> reporter: robin williams was a legend. but behind the zaniness lurked something darker, drug abuse and depression. and according to authorities in california, they got a 911 call reporting that williams was not breathing at his home in tiburon. they're calling it a case of suspected suicide. his representative saying williams had been battling severe depression of late. and abc news has learned williams recently checked himself back into rehab. for williams, life began in chicago in 1951. his mother, a former model, his father an executive at ford. he was surprisingly a quiet child. the first comic impression he did, imitating his grandmother to his mom. it was only in high school, in drama class, that he overcame that shyness. he went on to julliard, and