As designing women continues, Jim Avila and the case of a crushing blow. Reporter: Phoenix, Arizona, the valley of the sun, where hot asphalt bakes human tempers, delivering simmering trials and... See More
As designing women continues, Jim Avila and the case of a crushing blow. Reporter: Phoenix, Arizona, the valley of the sun, where hot asphalt bakes human tempers, delivering simmering trials and raven-haired killers. Jodi Arias, and now this woman, Marissa Devault. We thought that it was going to be the next Jodi Arias trial. But this is the Addams family. This is stranger than Jodi Arias. Reporter: Are these the hands of a murderess? Is this the face of a killer? Or is 36-year-old Marissa a victim? So battered by an abusive husband that she bludgeoned him to death? The prosecution telling a different story. She could face the death penalty. Reporter: Killer or victim? That puzzle that has stumped Phoenix, Arizona, since January of 2009. From the beginning. Just hours after the bloody attack that splattered the couple's master bedroom from floor to ceiling, Marissa Devault tells a story of constant abuse, verbal and physical. How did he hit you? With his fists. And where was he hitting on your body? All over the place. And he just kept hitting me. Reporter: Marissa even stands to show police how she says her husband of 15 years raped her on the night of the attack, choking her before forcing her on the bed against her will. So you came home and didn't want to have sex and he got mad? You wake up and he's raping you, hands around your neck. He likes that, he likes it because he can hold me here. At times, crying. Seeming completely distraught. At other times, smiling in an uncomfortable way that a seasoned detective would probably look at, and at the very least, find odd. Reporter: For police, it was an odd story and an odd victim. Dale and Marissa had met as teens in their hometown of lake havasu, Arizona, a party town known for outrageous spring breaks. They met up again years later in their 20's in Phoenix. By then Marissa had a baby. She was a stripper and according to her friend and nanny Amy Dewey, an opportunistic Marissa saw dale as a catch. What was the attraction? I think that she saw a man who had just graduated from refrigeration school and had the potential to make money. It was always about the money. Reporter: Amy lived with them for a time before their marriage. Was there any sense that dale was violent in any way? No. She would come home and try to pick a fight with him or try to provoke him and he would just tell her, "I'm not gonna fight with you, I love you, let's work this out." Reporter: Then came the day Amy was fired after a chilling conversation, if true, would foreshadow a future grisly murder. She came to me and said, "Dale is dreaming about having sex with you. I don't think that's appropriate." I'm concerned for your safety. Dale is dreaming about killing you with a hammer. You have to go." Reporter: Fast forward to one new year's eve. Dale is in his bedroom critically wounded by, yes, a hammer. Me husband -- Reporter: In the interrogation room, Marissa plays the battered woman card. I hit him with both hands. Reporter: But police don't buy her sob story. And prosecutors don't think a jury will either. Opening statements today in the case of a woman accused of killing her own husband. Reporter: The real motive for that tool-time thrashing, they say, was a big fat payday. Marissa is a woman who likes money, but more than that she likes easy money. Reporter: Prosecutors show the crime scene in vivid detail, displaying dale's deadly injuries. Arizona republic writer Michael meifer is in the courtroom. You know, she put a fist-sized hole in the side of his skull. Reporter: Then the prosecution begins to reveal a secret life that Marissa never spoke of. A past that includes working that pole at a strip club. The risky behavior. The boyfriends. The stripping. You get a picture of someone who doesn't have rules. Living on the edge. Yeah. Reporter: One of the lovers, they met on a website. So you began having sex the first day you met. Reporter: He loans her money, keeping meticulous track. This insurance money's gonna come through. Don't worry about it. Reporter: There it is, what prosecutors believe is the real motive for the murder. A big life insurance policy on dale earmarked to pay back her sugar daddy. A new insurance policy that was worth a million dollars that Reporter: It was not looking good for Marissa. But her defense had yet to start. And when it did, a blockbuster of its own. Until then, really nobody had said anything positive about Marissa. Nobody. Reporter: But Marissa had an ally, her oldest daughter Rhiannon, named after the Fleetwood Mac song. And she has a devastating story to tell about her stepdad dale. Her daughter came in and said, "Yes, dad hit mom." And said, "Yes, he had affairs and came home smelling of some other woman's perfume." And when the prosecutor brought up, "Well, didn't your mother hit your father as well?" She said, "Well, not as much as my father hit my mother." That was damning. Reporter: It was a tough defense for dale's family and friends to hear. But would it sway the seven women, five men jury? We know it was Marissa Devault in the bedroom with the hammer. You're not talking about who did it. You're talking about why did she do it? Did she have any justification? Do find the defendant count one first degree murder guilty. Reporter: Murder in the first degree. Guilty. This week, the jury ruling 36 year-old Marissa Devault, mother, stripper and gold digger, was now a killer too. It's unfathomable. Why did dale die? It seems like they proved in court that he died for money. Why did he put up with her, do you think? He loved her. She killed the one person who
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