Transcript for TV Interview Leads to Woman Going on Trial for Murder
Reporter: A curious feature story on the website of the ft. Worth, Texas, newspaper about a new kettle bell workout club. The owner is one Shelley Williams, who may look familiar, because at the time, she's the most infamous widow in Texas. Her husband Gregg, shot in the head in their king size bed, in their king size house. But now, less than a year after cremating her husband, Michele is the very picture of a merry widow. It's very upbeat, it's fast. Everybody has a good time with it. Reporter: Also having a good time, Michele's employee gene Wallis. We're in a group atmosphere so it pushes you more than you can push yourself. Reporter: You could call him an employee with benefits. A dozen years younger than Michele, they're now a couple. Much has happened since that interrogation room where Michele told two different stories about how her husband wound up with a bullet in his head. First she said it was murder. Then suicide. But police have been weighing the evidence. Based on the angle of the gunshot wound and other forensics, the medical examiner eliminated suicide, and ruled Gregg Williams' death a homicide. And remember, the crime scene showed no sign of an intruder. Crime scenes don't lie. People do. Reporter: Something else bothered police, how that little girl, Gregg and Michele's daughter Mikayla, slept right through a shooting in the next room. I think it's a reasonable possibility that children's tylenol, or something else, was administered to the child. Reporter: Some sort of drug to make her sleep. Yeah. Reporter: Police concluded only one person could have shot Gregg -- his own wife, Michele Williams. The motive, insurance that would pay out the better part of a million dollars. That sobbing in the interrogation room when the cops told her Greg was dead? Crocodile tears. She was arrested and charged with murder. But Michele doesn't sweat the small stuff. Soon out on bail, there she is, swinging kettle bells with her new boyfriend. Her mind was also getting a workout. She tells her son Andrew o'brien, it really was murder. What's more, now she wonders whether the killer might be her own son, Andrew's brother lee. She asked me, she said, "Do you think your brother could have done it?" She asked me if her own son could have killed Gregg. She had to plant a reasonable doubt that someone else could have been there that night, someone else could have squeezed that trigger. Reporter: By pinning it on you. Yes. Reporter: But police say lee and Andrew o'brien both have strong alibis. The brothers say they began to realize mommy dearest might be a monster. She doesn't even know what reality is anymore. She' lying so long, and I think that somewhere along the way, reality -- reality left. And so she just kept going. She knew nothing else. Lie after lie. She would attempt to kill dogs. If someone had a salt water fish tank, she would pour ajax in there and kill fish. Reporter: In Texas a murder charge can land you on death row. But not Michele. Her luck holds out. I don't know how she managed to do it. But Michele Williams managed to finagle a plea deal out of the state. Reporter: Prosecutors say Michele cleaned the crime scene so well, they didn't have much of a case. This is a circumstantial evidence case, there's no doubt about it. Of course not in small measure because she had altered the crime scene. Reporter: The deal, announced in a press release, requires Michele to plead guilty not to the murder charge in the indictment but tampering with evidence and deadly conduct. The recommended sentence will be just 18 years. In a jailhouse interview, Michele seems pleased with her bargain. With a plea deal I'm looking at a couple years before I'm out for parole. I'm actually, if you could say, looking forward to getting the sentencing over with so I can start moving towards the end of this hell. Reporter: But before she can be sentenced, Michele has another surprise. She's pregnant. Just before sentencing. And not only is she pregnant. She's pregnant with twins. Reporter: Sentencing was deferred until after Michele's due date. But prosecutors say the pregnancy turns out to be another lie to delay prison. The conception was an immaculate deception. But then Michele makes the mistake of a lifetime. She grants an interview to the national TV crime show "48 hours." Did you murder your husband Gregg? No, I did not. Reporter: There she goes again. Michele flip-flops on her story. She tells "48 hours" she's an innocent woman. And she pulls an old tried and untrue story out of mothballs. The man in black did it. There was an intruder in the house and that person killed my husband. So she had already pled guilty, and then she gets on national television and says, well, what I really meant was, I'm not guilty. What I really meant is, an intruder came in, and I really meant that I have a good idea who the intruder was. Reporter: It doesn't play well with the judge. He revokes the plea deal and orders Michele to stand trial for murder. The woman accused of shooting her husband in the head just shot herself in the foot. You have a fifth amendment right to remain silent for a reason. Our U.S. Constitution protects you from the actions of the state. What the U.S. Constitution cannot protect you from is yourself. Reporter: When we come back,
This transcript has been automatically generated and may not be 100% accurate.