no secret what the biggest obstacle was for lead investigators captain dan hally and detective jackiewe don't even know for sure that we have a death. we believe that in our gut. >> reporter: as the cops dug deeper into the background of the husband's friend david stone, the case suddenly became way more complex. a mind blowing theory, maybe this wasn't just about one wife, rachael, maybe it was about two. the investigation had led them to the city maintenance yard where stone worked. a fellow employee there had related a conversation he'd had with david stone awhile back. >> it surfaces that there had been some conversations between david stone and this individual about a plan to kill stone's wife for $10,000. >> reporter: then stone, the story went, came back sometime later and told the maintenance yard guy to forget they'd talked. he'd arranged a plan "b" for murder. >> and that later that that deal was canceled because stone had reached an agreement with charles capone that they would kill each other's wives. >> reporter: i'll kill your wife if you'll kill mine. this is the stuff

rachael went to the county sheriff's office and told her story to captain dan hally. >> she was extremely frightened. she believed an individual that she had dated for a couple weeks, by the name of william slemp -- he was the one stalking and harassing her. >> reporter: so when rachael left that day, what was the plan? >> she was going to essentially put together the information that she had, and then we were going to meet again that friday. >> reporter: did you see her again, captain? >> i talked to her on the phone, but i never saw her again. >> reporter: not long after leaving the sheriff's office, rachael applied for a restraining order against william slemp. it was the weekend. the two boys had visitation with their dads. it wasn't until mid-morning the following monday that people began to realize that something had gone very wrong. rachael's daughter amber got a message that her mom hadn't shown up for work as a medical technician. totally unlike her. >> yeah. i knew immediately that it was bad. amber got word to sister ashley, and they raced to their mom's home. when there was no

. >> reporter: captain dan hally testified that the defendant had been behind those head-game calls all along. capone even admitted as much to him. >> he told me that he had been involved in the stalking and harassment. >> yeah, i know she was afraid. >> reporter: ashley and amber, the daughters, recounted the terror of their mom's ordeal. >> she had the feeling like her life was going to end, a dreadful feeling. >> reporter: the prosecutors zeroed in on charles' character. jennifer norberg recalled what her friend's neck looked like after charles allegedly attacked rachael four months before she disappeared. >> i observed that she had some red, dark colored marks on her neck. >> reporter: then, prosecutors produced a business neighbor, an actual eyewitness, who saw charles arguing with a woman outside his auto shop that fatal night. >> she jumped out of the car, flailing her arms right up into his face. >> raise your hand and be sworn please. >> reporter: so far, the testimony was all appetizers before the prosecutors' main course. their head-snapping all or nothing star witness, none