Transcript for Investigators set out to prove that Martin MacNeill killed his wife: Part 6
To take one more life. Here's when Alexis surprised him at Christmas. It shows a little bit of who we felt like my father was. We would've done anything for him and my mom. None of us ever suspected that this person that I knew as my father, it was an act the entire time. Our entire lives are a lie. I really feel like to him we just were a part in a play. I'm really scared. It's been just over a year since he's been in jail and that was really the first time that we could sleep really while at night. Knowing that he's not gonna be around the corner. And now, if he gets out of prison for the fraud, then he's like, all right, I got away with the grand ultimate scheme, I shipped my daughter away, stole her identity, gave it to the lady that I had an affair with. Killed my wife, was able to get rid of my other children, and so he comes out on top, and he comes out unharmed. Alexis has temporary custody of her sisters. But she's afraid that won't last. He'd come down here so many times trying to get access to the kids. Saying that he's going to walk in Ada's school and take her right from school. Saying he's going to grab elle and Sabrina and take them back to Ukraine and drop them off where no one will find them. Guess what, if I want these children I'll come and get them. I know you can, dad. That's what I don't want. That's what I want to fight against. You know, when they're fearful of you and they don't want to see you. If I change my mind I can get them now. Understand that. I can come anytime I want. And now investigators have Dr. Martin Macneill and his lover, where they want them -- behind bars. The Macneill family stunned, gypsy Willis pleaded guilty to four felonies, but they believe she did something much worse than identity theft. They say she conspired with him to murder their mother four years ago. At the last sentencing hearing, the only thing he said to me is, I hope you're happy, Alexis. I hope you're happy with what you've done. Investigators became convinced that martin had killed Michele because he wanted to be with gypsy. While martin's serving time, the investigators have this very short window to get charges put together to get him on trial for the murder of his wife. All of Michele Macneill's sisters, her mother, her daughters believe that martin Macneill killed her. What do you think? The reason we have a homicide investigation open right now is that we believe that there is probable cause there is foul play involved here. And we believe we are on the right track. The first thing they needed to do was visit the medical examiner and get her to change the cause of death. The manner of death was listed as natural causes. That was a significant report, in that it looked like it was just a natural death, and there's no homicide. Sometimes we would stand toe to toe, yelling at each other, "Show me that this is a murder. Give me any information." It was a challenge. It was a huge challenge, because police had gathered very little evidence the day that Michele died, so they went back and piece by piece tried to put together the events of what happened in the Macneill home. One of the most alarming things in the case was the discrepancy of the positioning of Michele's body in the bathtub. Michele was originally found by her youngest adopted daughter, Ada. Martin Macneill had gone to pick Ada up. He brings her home. He told her, "Ada, go check on mommy." She really remembers is vividly even though she was just 6 years old. She had to see something very horrible. What did you see when you walked into the bathroom? She was just laying down, in the bathtub. She was laying down, in the bathtub? She had to wet her hair. Was she all the way in the bathtub, or just part way in the bathtub? All the way. And had you ever seen your mom wet her hair like that before? I don't want to talk about it. How does it make you feel, talking about your mom? Sad. I can't believe that she was used that way. The thought of her 6-year-old daughter finding her body, it haunted me, that for the rest of her life Ada would remember mommy in the bathtub. Ada had described finding her mom's body laying inside the tub with her head above the water. And that was the exact same position that the neighbor who first entered the house found Michele's body in. Michele was laying on her back in the tub, face up, with her head underneath the faucet. Your dad said your mom's head was under water. Yes, laying face down. You mean bent over the tub? Yes. It seemed like martin was trying to create an image of his wife getting into the bathtub, but had fallen and slipped on her way into the bathtub. Does anybody corroborate martin's version of events that morning? No. So it's martin on his own, and all the other witnesses on the other side describing pretty much the same scene. That's correct. Martin definitely appeared to be up to something at the crime scene. When he called 911 at first, he wouldn't give a clear address. I need an ambulance right away! He was yelling very hysterically at me. So I kind of had a general area of where the call was probably coming from, but not an exact house address. So the ambulance doesn't know where to go. And precious moments are lost searching for the address where this call originated from. There were a lot of things that martin had done that day that seemed very suspicious. A neighbor came over, and they tried to lift her out of the bathtub and put her on the ground and started performing cpr right away. Martin and I did cpr on her for what felt like several minutes. He, as a doctor, presumably could perform that cpr. There was definitely no response from Michelle. I do not recall the chest ever rising. There was no water aspirated out of her lungs until the paramedics arrived. As soon as the emts start performing cpr on Michele Macneill, water begins gushing from her mouth. Was he really even trying? It seems as if Dr. Martin Macneill is doing everything he can to delay saving her life. That's nothing compared to what happens next. People start coming out of the woodwork, people with damaging information about martin Macneill.
This transcript has been automatically generated and may not be 100% accurate.