Transcript for Girlfriend Convicted in 'Stiletto Murder' of Boyfriend
Ryan smith continues with more of designing women. Are you reporting an assault, ma'am? I hit him with my shoe. He's bleeding a lot. He started beating me up. Reporter: When Houston police received Ana Trujillo's desperate 911 call, they raced to her boyfriend's high rise condo and walked into a slaughterhouse. The crime photos in this case were especially gruesome. The blood spatter. The victim still lying there. It was a tragedy and it was horrible. The hallway was streaked with blood. The deceased, medical researcher Stefan Andersson barely recognizable from more than two dozen stab wounds to his head, face and neck. All from the heel of one of Ana's blue stilettos. And on a glass table nearby, a macabre sign, Trujillo's book of tarot, turned to the picture of death. Instantly, the police officer was suspicious. He just yelled at me and took his gun out and he told me to -- to get down on the ground. I thought they were there to help us. Ana tells police Andersson had attacked her, that she killed him in self defense. But though she was drenched in blood, police say she doesn't look injured. She gives a rambling, disjointed statement. It's a meandering sort of my life up till now three hour tape in which she talks about what actually happened the night of very briefly. Reporter: The cops have heard enough. They put her under arrest. You said you felt like a fool. Why? They're blaming me, they're telling me that I killed him. I am not a murderer! Reporter: She is booked, posts bail. Put under house arrest. Each day, new allegations surfaced about herpast. A friend remembers a startling attack. She knocked me out. Reporter: And remember the londale hotel where her friend Jim Carroll once lived? He had the most jaw dropping tale of all to tell. She told me that if anybody ever messed with her, she pulled her shoe off, she said, "I'll get 'em with this" and it was a big stiletto heel. The trial began last week in a burst of lights, cameras and bravado. Feeling confident? Do I look scared? Reporter: From the beginning, the prosecutors pull no punches, focusing the jury on that killer heel. Really the star witness in the case. Over and over, they demonstrate the brutality of the crime. In trial, we saw an x-ray of the shoe. To the naked eye it just looks like a cobalt blue stiletto high heel. But once you saw that x-ray it looked like an ice hammer. He had ten puncture wounds on his head, fifteen to twenty around his neck, face, and arms. That is excessive for a lot of people. Excessive? What he was doing to me? He was enraged. He hit me on the head with my own shoe. Reporter: Even though his case is far from a slam dunk, her lawyer is still confident. And whether she hit him once, 25 times, 50 times, if she felt her life was in danger, the jury can't convict. Reporter: To prove the case, Carroll has to convince the jury that Andersson flew into a violent rage back at his apartment. These photos show bruises, but it wasn't clear how or when she got them. The defense wanted to portray her as victim. Because she had to. Reporter: But remember that surveillance video from the apartment, the last images of Andersson alive. He seems calm and collected. Carroll says what you can't see is his blood alcohol level. We've all seen people who drink a lot who act one way in public and go home and then act another way. Anna was alone in Stefan Anderson's apartment. And he went off the deep end. Reporter: Did the mild mannered professor attack his girlfriend in a drunken, jealous rage? She talked about being smothered and he was grabbing her, that's when she hit him with her shoe. Reporter: But it's the murder weapon itself. That $29 stiletto shoe, that could come to Ana's rescue. It's not a gun, it's not a knife. It's not the typical thing someone would use to kill someone. So that could help the defense in saying, she just grabbed whatever she could. With the evidence mounting against her, Ana is thinking about taking the stand. Are you confident enough that the confession I did on tape is enough? If I put you on the stand, they can ask you about certain things that may have happened. Reporter: But at the last minute, she decides it's too risky. And with her fate in the balance, Ana prepares her daughter, siana, for the possibility that she may be heading to prison. We have to be prepared for what's to come. We might have a conviction and I want to tell you I love you very much. Reporter: On the morning of April 6th, the sun rose over a perfect spring day in Houston. Closing arguments in the Trujillo case were about to begin. It won't be until your break that she ceases to be the stiletto stabber. If she reasonably fears death -- Reporter: She's now a convicted murderer, sentenced just this afternoon to life in prison. And she still refuses to wear it. We all have an opinion, but until you find yourself in a situation, you don't know either. Reporter: You don't know what you're going to do when that happens? You think you do, but you don't. Reporter: In spite of everything, you loved him. I have no closure. And it's not my fault. After seeing the evidence, was it self defense, or murder? When we come back here tonight, when getti citing a facial can turn deadly.
This transcript has been automatically generated and may not be 100% accurate.