Transcript for Head-spinning 2005 case of woman left for dead connected to three other assault cases
It's about 8:00, 8:15 in the morning. You've got a Florida power and light worker driving up the street and notices what he thinks is a body. The woman was air lifted to the trauma center in critical condition. She has cuts on her face, swollen jaw, bruises on her body. She was unconscious for almost 24 straight hours. Reporter: A woman left for dead in a Florida abandoned lot. I have a Jane doe on my I'm running into nothing. Rorter: The hunt for her attacker setting investigators on the trail of a serial rapist. I knew this was the guy, and I was going to catch this guy. Reporter: And the moment caught on camera that leads detectives to his doorstep. You were there. I did not do that. This is the most remarkable piece of detective work that I've ever come across. Reporter: She woke up in the hospital, raped and badly beaten with no memory of what had happened. I remember voices around me, somebody asked me what was my name. I was in pain. Very, very painful. Reporter: The Ukrainian, a cruise ship worker was staying in a hotel in February 2005 when she was attacked. I wanted to have an occupation in my life. I wanted to be someone. But I guess it's all changed. Reporter: Investigators zero in on the regency hotel where she'd been staying the night before. We have 16 cameras covering the whole perimeter of the hotel, including parking lot, the entrance, the exits. The lobby, the restaurant, the lobby bar, the front desk, the back exits. Security cameras catch her leaving at 3:33 A.M. In a red jacket and returning at 3:40. I went to the gas station to buy a calling card. I used to call my mother often in Ukraine. I love her and miss her. She misses me. Reporter: She's seen in the lobby getting in the elevator and never seen by those cameras again. It's the last we see of her. That's how we believe she was attacked in the hotel. The effort to find out who had done this to her was hung up on the question of how had she ended up eight miles away in the weeds. Reporter: For months, the investigation stalls, with dead ends and false leads. I believe no matter what happened, it was going to be in the videotape. Reporter: Then the hotel hires private eye, Brennan. She goes out early in the morning. When she returns, there's a big, large man standing with her, and she has a quick conversation with him. And they get onto the elevator together. Reporter: Later, the mystery man seen leaving with a Sometimes the smallest details ultimately end up cracking the case. This was the defining moment in the whole case right here. Ken observed that when this man pulled the suit case out of the elevator he had to give did a little tug to get it out of the elevator and into the floor. A light bulb went out and I said she's in that suitcase. Reporter: Detectives discovered their possible suspect worked for a catering company hired by the Miami boat show and was living in Frederick, Maryland. His name, Michael Lee Jones. I said we've got to get some DNA from this guy. Either voluntarily or without his knowledge. Reporter: He flies to Maryland to interview Jones. He's cool as a cucumber. Leaned back in the chair. No hiding or stuttering, looking for something. Reporter: He confirms he was working in Miami and staying at the hotel where she was attacked. I flat out asked him, did you do it? And he says, well, no, of course Reporter: Does he seem believable at that point? Yes, he does. And then I asked him would you be willing to give a DNA specimen? Because I have specimens from the rape. And he said absolutely. Jones readily gives up his DNA, because he believes they can't link him to this crime. Reporter: But the results tell a different story. I called Ken up. I says, you're not going to believe this. And he goes. It's him. I go no kidding. I knew it was him. I get an arrest warrant, go back to Maryland, meet up with Ken and members of the Frederick police department, and we go to Michael's apartment. You're being charged with rape, all right? She says I raped her? We already hit on the DNA. Now it's just the question of interrogating him to see if I can get this guy to roll on it, right? Look at these. I didn't do that. You were there. I did not do that. Once we started to throw the fact that, you know, obviously he was under arrest for this kidnapping and rape, his story changed. Give me your version of what went down. You only get one chance. All right, I'm going to be straight up. The only thing he's going to come up with is she was a prostitute. I paid for her. She was fine when I left her. I have no idea what happened to her, okay. Obviously, hookers or whatever, we were talking to her, want to have some fun. Then what happens next? You go to her room? She go to your room? Went to her room. You went to her room? Mm-hm. And then she whispers in my ear, so I give her $100 and I left. Unfortunately for Jones, his story doesn't match the surveillance video. There wasn't any exchange between them that would been indicative of soliciting a prostitute. Reporter: And then there were questions about him leaving the hotel with the suit case with and returning without it. I went to get a soda. Not in the morning. What stuff did you bring up here? All I had was my suitcase. I said what was in the What do you have in your back when you went out to your car? My clothes. How much clothes do you have? I think two weeks. How much stuff, how big was your bag? When Brennan drills down on what exactly was in the suitcase, Jones actually pauses, which the investigators know they've now hit a nerve. How heavy was it? Was it fairly light? No, it was heavy. I had my X box and all kinds of X box, anything else in there? Clothes? Books. Got books? You're an avid reader? What kind of books do you like? I have no idea. I can't tell you the name of the book I just took out of my pocket. Who goes and leaves, takes their clothes out to the car before they check out? Nobody. Who's 6'4", weighs 380 pounds, has some underwear and an X box in a suitcase and needs two hands to pull it out of a crack? Nobody. Doesn't make sense. Doesn't make sense, because it's all bull . What is true is that he already beat this girl. He's dragging her out. He's gone for an hour, because he's looking for a place to dump her, because he thinks she's dead. Would you be willing to take a polygraph exam? Sure. Reporter: Jones fails the polygraph test but continues to maintain his innocence. So you don't know what happened to her or how it happened to her? No. Reporter: Michael Jones is charged with sexual battery and kidnapping, but prosecutors are not convinced they could get a conviction. Prosecutors decided they had a case of he said/she said. They didn't feel they could win a case if it went to trial. You don't know the way that a jury would feel. So the prosecutor's office decided to offer him a plea. Reporter: Jones ends up pleading to a reduced charge, and the case never goes before a jury. His prison sentence? Two years. I was upset. I just told them, you can't, you can't let this guy out. I was angry. But I couldn't do anything. I'm not familiar with the justice system. But I was upset. Yes, I was upset. Reporter: But Ken Brennan isn't bothered. He has a hunch that Jones has done this before. Ken Brennan knew that he was dealing with a serial rapist, and he was proved right. Reporter: Authorities enter Jones' DNA into a FBI database and find he's a match for two other victims. Jennifer Russler who was raped in Colorado Springs in 2005 and this woman whom we're calling Rachel who was raped in new Orleans in 2003. She helped police create a composite sketch at the time. Seeing that sketch next to his face, it was extremely satisfying. I just felt like yes. Reporter: Ultimately, Jones was convicted in Colorado on multiple counts of sexual assault and given a sentence of it 24 years to life. Then in 2015, he pleads guilty to two counts of forcible rape in Louisiana and was sentenced to 45 years. Reporter: You gave almost two year of your life to this case with. How did it feel to finally see this guy brought to justice? I gave two years of my life investigatal wise, but the victims give a whole lot more. The victims are the heroes here. I feel heartened that the criminal is where he's supposed to be, and he never gonna hurt nobody in the future.
This transcript has been automatically generated and may not be 100% accurate.