Tonight here, a mother, a wife, living in her beautiful home. An indude intruder breaks in and shoots her husband dead. But Matt Gutman with the truth in between the lies. Reporter: Drill a well in... See More
Tonight here, a mother, a wife, living in her beautiful home. An indude intruder breaks in and shoots her husband dead. But Matt Gutman with the truth in between the lies. Reporter: Drill a well in Keller, Texas, you don't get crude, you get cash. And 40 year old Gregg Williams was rolling in it, a self-made businessman, getting rich with his computer security company. Now sharing a little palace on the prairie with his wife, 42 year old, Michele, and their 4 year old daughter, Mikayla. Gregg and Michele both twice divorced, but it felt like this third marriage would be the charm. Michele's grown sons from previous relationships, lee and Andrew o'brien, say her marriage to Gregg was a fairy tale. He always treated her like a queen. Anything she wanted, she got. Reporter: The family renting a mcmansion with a pool out back, his and her Mercedes in the garage. Money. He's got the money, he's got the party lifestyle. He's accomplished, and he's head over heels for her. Reporter: Quite a change for the woman who had struggled as a teen mom to raise three kids, living hand to mouth. We were living in motel rooms if we could, bouncing around, couch surfing. Reporter: Michele, now the kind of bride who shows a little leg. Gregg, the kind of guy who buys his wife a yogurt shop to keep her busy. Perfect, what with her new taste for the sweet life. Gregg spending his spare time on alpha-male activities, karate chopping cinder blocks and body building. He was like a frat boy, like literally, through and through. He was a jock, but a genius at the same time. Reporter: But one October night, the cowboy camelot came to an end with a single gunshot. 911, where is the emergency? Reporter: That's Michele Williams, calling for help. Gregg has been shot. Someone shot my husband! Reporter: This is actual police dash cam video from some of the first officers arriving on the scene when they discover Michele distraught with a nasty goose egg on her cheek. Who else is in the house? My 4 year old and my husband. Your 4 year old and the husband? Reporter: Hoping to shed more light on the attack, police bring Michele, their only witness, down to the station. Then, as a sympathetic officer holds her hand Michele tells sergeant John Mcgrew an unbelievable story. Walk me through the story that she told you. She was asleep. Woke up by an intruder. Reporter: Michele says she woke up as an intruder in black was breaking in through a back door. The bandit passed by 4-year-old Mikayla asleep on the living room couch, and approached the bedroom. There, he ran into Michele, and knocked her out. She was struck by an unknown object. Reporter: Police later find a wrench at the scene, the right size to plant that painful bump on her cheek. That's what actually kind of knocked. It knocked me out. Reporter: Michele says she is still groggy when she sees the man in black standing over Gregg. There is a gunshot. And the intruder disappears through a back door. I screamed and I ran over to Greg. And I reached for him. I grabbed ahold of his hand. And I saw blood running down the bed. Reporter: Gregg has been shot once in the head. And eventually, there in the interview room, sergeant Mcgrew informs Michele, her husband is dead. There's not much I can say in this. Gregg is deceased. Reporter: The widow Williams is inconsolable. Reporter: The story catches the eye of the media, including TV's queen of crime, Nancy grace. Cops find daddy, shot dead in his own bed. Reporter: Who was the intruder in black who shot Gregg? Turns out there is no shortage of suspects, because Gregg's gilded life had a gritty side. He had an edge to him. Rubbed people the wrong way. He knows drug dealers and bad people. He's kind of like a Dr. Jekyll, Mr. Hyde. Reporter: Michele, trying to help identify that killer in black, mentions others police might want to talk to, including Gregg's ex-wife Kathy Williams. Him and his ex-wife fight a lot. Reporter: She doesn't mention the two men in the world who may have disliked Gregg the most. His stepsons, army vets, Andrew and lee o'brien. How much did you not like him? I hated him. I -- I don't throw that word around lightly, but I literally hated him. Reporter: As sometimes happens, the stepchildren felt unwanted and unwelcome by their mother's new husband. Was there ever a point that you were happy that he was dead? Yes. Immediately. When they told me he was dead, it was like, "Cool, whatever, how's mom?" Reporter: Both you and your brother openly say you despised Greg. Uh-huh. Reporter: Did you have anything to do with his murder? No. Reporter: But police are beginning to wonder whether there was an intruder at all. Keller police captain Brenda Slovak, the lead investigator, drives us to the big house on Jacob avenue. And back to the night of the shooting. And from right here, you could see the body? Correct. I could see him in the bed. Reporter: But in that bedroom, there is not a single sign of a struggle. And in a house loaded with valuables and $20,000 in cash, the killer takes nothing and, leaves nothing. Did you ever find fibers or any DNA evidence or any other kind of evidence of an intruder? No. So, what? You have an unknown assailant break into his home. Shoot him dead, and leave, for what? Reporter: And then police practically trip over the most important evidence in the case, right here in these crime scene photos. The murder weapon. The very recently smoking gun. Gregg's gun. Yep, shot with his own gun. If someone's going to come into the home and try and do you some harm, normally you would bring your own gun. Reporter: And right next to the gun, the fired shell casing and the wrench possibly used to hit Michele. Arranged, neat as a pawn shop show case. You saw this picture, what was the first thing that went through your mind? Staged. Staged. Reporter: When you were sitting across from her, did you ever think that this woman is lying to me? Oh, yes, sir. Reporter: Back at the police station a suspicious sergeant Mcgrew tells Michele the crime scene suggests only two possibilities. Either she shot Gregg, or Gregg shot himself. I did not hurt my husband and he did not hurt himself. There was a man in my house. Reporter: She denies it, no fewer than six times, until this moment. If he self inflicted it, you need to tell me. I mean, this is it. We're getting to wit's end. You've got to be honest with me, Michele. If he did it and you covered it up, just tell me. He did.#, Huh? He did. And she said, "He did it." He did it. She immediately folds, and went, ah, okay, you got me. He shot himself. Reporter: Michele admits she's told a pack of lies and now offers a second version of Gregg's death. Michele now says, she was sleeping on the couch with 4-year-old Mikayla. She hears the gunshot, and goes into the bedroom to find Gregg had shot himself. She cleaned it all up and arranged things to look like a home invasion. I knew I had to make it look as if there was a burglary. Reporter: And get this, to really sell the story, Michele says she hit herself in the face with that wrench. I went like that, thinking I would just have a little bruise. And that really backfired bad. Reporter: Michele says she only wanted to protect their 4 year old daughter Mikayla, and Gregg's reputation. After spending five hours in the interrogation room, police finally release Michele, who soon finds consolation in comfort food. The very morning after Michele Williams goes out to breakfast to ihop and basically orders the lumberjack breakfast. She's not worried about her dead husband at all. She's living it up. Sausage, pancakes, eggs, the works. Reporter: But police are finding Michele's stories hard to swallow. They have more questions than ever about the night Gregg died. Like, how did 4-year-old Mikayla sleep through a shooting in the next room? Somehow, Mikayla, their daughter, slept through it all. How is that possible? Reporter: Could clues from a little girl unravel the mystery of her father's death?
This transcript has been automatically generated and may not be 100% accurate.