By snatching his seven-year-old daughter from her mother's custody, after a bitter divorce, the man calling himself Clark Rockefeller blew the lid off a lifelong con game, which had culminated with his posing as a scion of the famous dynasty. MARK SEAL learns how the impostor charmed his way into exclusive communities, clubs, and financial institutions marrying a Harvard M.B.A.; working at Kidder, Peabody; and showing off an extraordinary art collection until his arrest brought him face-to-face with his past and with questions regarding skeletal remains dug up in a California backyard.