Transcript for Hotel where rape victim was staying hires private detective after she sues: Part 3
who's kind of right out of central casting. I mean if you've ever met him, you remember Ken Brennan. He wears open collars and gold chains and rings on his fingers and he rides a motorcycle. He speaks with a New York long Island accent filled with profanity. He is funny, blunt, smart. If he's on a case, he's going to solve it. What is it about this kind of work that attracts you? Who doesn't like catching bad guys? I've always enjoyed doing, even when I was a youngster. I've been working in law enforcement since 1974. I was a police officer before as well as being a federal agent. Is it true that you've never taken a sick day? No, I really haven't. When you enjoy what you're doing, it never seems like a job then. So when the Miami case dropped into your lap, what did you think? The mere fact that nobody knew how she got out of the hotel. That she just kind of vanished. And especially because it involved a sexual assault. This is a guy who feels determined to get justice in cases that involve sexual predators. In fact, he told us that he carries around the arrest file of the very first sexual predator whom he interrogated. They're the worst crimes, I feel, of all of them. And there's too many of them out there that aren't solved. One of the big challenges in sexual assault cases is that it's typically not funded as much as robbery and homicide. And so, what has is that sexual assault investigators get overwhelmed. And these cases aren't easy to solve. As weeks turn to months, now nine months in the investigation and they still have no idea who attacked her. Were you thinking at any point that this case is just unsolvable? I don't like to think that, and I really didn't think that. I always kept hope that something would eventually solve the case. I don't like to give up. By now, Inna's filed a lawsuit against the hotel alleging negligence in the security that they had that allowed this to happen. We felt they could have had better security. They weren't monitoring the security cameras correctly. They let an assailant onto the grounds of the hotel. Why and how somebody would get into your room without the key. How? The hotel is denying any wrongdoing so that's where Ken Brennan comes in. When a hotel gets sued in a big case like this, they will typically hire their own investigator to determine the facts as best they can. We have to clear the responsibility of the hotel. What happened in our hotel, it can happen in the best hotel in the world. The biggest glaring thing was is that nobody really knew how everybody loves a good mystery. Everybody wants to be the ability to solve something that somebody wasn't able to do before. So, of course that would be rewarding. What did you think of Ken Brennan when you first laid eyes on him? This guy is going to drive me nuts. Most police officers don't like pis. How did you get him to accept and to trust you? I said, "Hey, listen, Allen, I'm not going to mess up your case, you know. I'm not going to screw it up." We're going to solve this thing. We're going to be a team, we're going to work it together. You don't like P.I.S, but yet you trusted him. Why? There was just something about him that was honest. I really felt that he was going to do what he said. One of the first things that detective Foote shares with private investigator Ken Brennan is that the DNA doesn't match Peter dimouleas or George Perez. Those two guys are eliminated, but now, Ken Brennan's trying to figure out what did happen. Then he begins to share with the detectives suspicions about Inna. Could there be more to the story? Could there be more about her? So he begins knocking on doors around the neighborhood where she was found. I bothered to take the time, and to surveil her activities while she was still in the neighborhood. There was nothing indicative of her being a prostitute. So you ruled that out. So I ruled that out pretty readily, in the very beginning of the investigation. I was very, very upset about this. Very, very upset. I knew who I was. I know who I am. Another mystery, the tape shows the victim entering the elevator at 3:41 A.M., and then her room key swipe is showing recording at 3:58. So, how did you explain those missing 17 minutes? There seemed to have been a problem, they thought that maybe she might have went to another room, went and saw somebody. I said, "Well, listen, did anybody bother to take the time to find out if the time stamp on the security cameras, if that matched the time stamp on the card access system? Which nobody ever did. And it turns out, when we did do that, there was a 17 minute lapse. So that mysterious gap in time wasn't really a mystery at all, just a clock that was 17 minutes off. I knew immediately that after she was on that elevator, she went up directly to her room. One of the theories that occurred to Ken was because Inna had asked for a lawyer right in the beginning, there was some thought that this was sort of eastern European organized crime con. I thought that in this particular case that there might have been a possibility the whole purpose was to try to obtain money from either the insurance company or from the hotel itself. It happens all over the world. Because she was filing the lawsuit against the hotel, a big lawsuit. Exactly, and she didn't make a very good witness, because she flip flopped on a lot of statements that she'd given to police. It Ju make me to laugh. I mean, I don't know from where did they take this, and who came up with this idea. I believe that no matter what happened, it was going to be in video tape. How much footage were you going to have to comb through? Because there were a lot of cameras in the hotel, right? Hours upon hours upon hours upon hours. It was extensive. That's something that you have to go through almost frame by frame. Frame by frame? It's a countless amount of hours. Ken has a very deliberate way of looking at the cases that he takes. He knew she had to have left the hotel and he believed from everything that he understood about the way the camera systems worked that that had to have been recorded. You had to watch each and every frame, on every video, because we were originally looking for possibly an employee that might've moved one of the cameras out of the location it waoriginally at and maybe possibly snuck the victim past that way. Slowly but surely, Brennan has began to eliminate pretty much everybody they've looked at except one guy. She goes out, on the video, she goes out of the hotel early in the morning. When she returns, there's a big, large black man, standing with her and she just has a quick conversation with him, and they get onto the elevator together. I'm trying to look to see -- do they look like they know each other. Because again, I'm thinking, this could still possibly be a scam or something like that, and after you keep reviewing it, it doesn't look like they have any kind of familiarity. He's just offering her to walk in front. She's not acknowledging him like she knows him. So Brennan has kind of given up on this whole conspiracy theory idea. It eye peered in the video this was just a chance meeting. It didn't appear to be staged at all. Now he's moved onto something else. He's looking at this one guy on the elevator but that seems like a stretch as well. Later on during the video, he's seen exiting the elevator, so we follow him to another camera and he goes off the property. While I'm watching the video of this person coming off the elevator, I went through this frame at a time. Sometimes the small details ultimately end up cracking a case. This was the defining moment in the whole case, right here.
This transcript has been automatically generated and may not be 100% accurate.