dennis murphy (voiceover): debra viegas's world had been turned upside down. lewis had been murdered, and debra's estranged husband tony >> reporter: debra villegas' world had been turned upside down. her best friend, melissa lewis, had been murdered and debra's estranged husband, tony, was charged with killing her. >> people thought, "debra's psycho ex-husband has murdered melissa." you know, i was just overwhelmed with guilt and shame. >> reporter: melissa's murder weighed heavily on debra's mind, as well as the mind of her boss scott rothstein. but scott seemed to be rattled by something more than just melissa's murder. for some reason after tony's arrest, rothstein beefed up his own security. who was he afraid of? >> obviously that he was next. >> reporter: but if melissa's murder had been solved, why was scott still worried? debra knew because she was privy to a secret that threatened to send even more people to prison, and to destroy scott rothstein's reputation as a high-profile mover and shaker. >> he could pick up the phone and call and make things hap