>> since michael had an alibi, investigators turned their attention to karyn's current boyfriend, david swann. >> he'd had some run-ins with law enforcement. he had been put on probation in the past. he had pretended to be or impersonate a law enforcement officer in the past. he had spent time in a mental ward at a hospital. >> 34-year-old david swann had been dating karyn for only a short time. a background check revealed a disturbing incident. >> he had been involved in killing a deer and then had put the deer over a swimming pool and had used a chainsaw or like instrument to clean the deer. and due to the fact karyn had been dismembered and we weren't exactly sure what the means of dismemberment were, we were interested in information like that. >> and david's alibi was shaky.