investigators to prove that this mysterious conman was also a killer. but was the case as clear-cut as it seemed? there was no motive. there was no reason he would have done this. for the first time, hear from the detectives who helped crack this puzzling case and from his ex-wife. i thought he was very intelligent, funny, very charming. for decades, he got away with a web of lies. would he also get away with murder? i can fib, certainly, but i have never hurt anyone. tonight the mystery of the man with so many faces. i m lester holt, and this is dateline, behind closed doors. here s mike taibbi. it was a brutal crime, buried over the years by dirt and lies, but there he was finally in a los angeles county courtroom to stand trial for it all. he came here with nothing, and then he ended up as a fake rockefeller. the world first came to know him as a phony rockefeller, who made headlines for duping a string of bright, if gullible women. they couldn t tell