robert durst. like quicksand, it's sucks you in. >> bob is endlessly fascinating, and always surprises me. >> he was certainly elusive. material, sometimes desperate. always in motion. we track him, his dissent, his change detour off the road, off the grid. a life that no one, not even his family or close friends could fathom. >> he has a good heart inside. i really think so. ♪ ♪ ♪ >> we begin with two people who know and love the man that they called bobby. godfather and son. close friend of more than 40 years, long before the rest of the world heard from him. when did you meet him? >> we went to high school together. >> stewart and emily altman, spoke to us after robert durst was arrested. >> they show assad of bob that he is not a monster. he has a heart. but it has caused me a great deal, that i can't get up my head around, is what happened to bob. it's hard. >> they altmans, shared personal photos. and the story of bob that they lived and breathed. starting with the family disaster that tormen