Reporter: It is a haunting mystery. Who attacked a young woman and left her for dead in this vacant cul-de-sac? Detective Alan Foote's search for clues has become an xer sunrise frustration. So, where... See More
Reporter: It is a haunting mystery. Who attacked a young woman and left her for dead in this vacant cul-de-sac? Detective Alan Foote's search for clues has become an xer sunrise frustration. So, where did you turn next? I start following other leads. Suspects in the case. Reporter: There's no shortage of early suspects. For starters, that friend who was out with inn the night she was attacked. He's 52-year old peter dimouleas, a Greek national and -- like inn -- a cruise line employee. He asked me, what happened with inn? Reporter: Peter confirms inna's account, a dinner and some drinking in coconut grove, then a friendly parting of ways around midnight when inn takes a cab back to the hotel. He cooperates fully with the police. Why I have to worry? I don't worry. I know I am not on the crime. Reporter: But detective Foote uncovers this troubling fact -- dimouleas has been arrested just months before, after he and inn had a dispute at a local nightclub. Peter felt that there were some unsavory characters there, and wanted her to leave. So, she did not want to leave, and he kind of grabbed her by the arm, and they got into a little argument, and an officer working security arrested him for domestic violence. Reporter: Did that make him a suspect in your mind? Partially. Reporter: Then there's this guy. The hotel night manager, George Perez. The very first time I met George Perez was, he looked at me and he said, "Oh, my god, I hate cops." Reporter: Pretty blunt, pretty honest. Oh, yeah. I'm used to it. Was I nervous? Absolutely, I would have every right to be. Reporter: Along with that instant hostility, Perez attracts police attention because he's seen with inn in the lob biaft after she returns from her night out with peter. You can see the sleeve of her red jacket on the front desk security camera here. At some point in time, I do see inn coming and going from the hotel. I see her talking to the desk clerk. Reporter: Then, at 2:16 A.M., an odd encounter. He left the front desk unattended and went into the elevator with the victim and was gone for approximately 15 minutes and then came back down alone. Reporter: Perez initially said he helped inn to her room because she'd had too much to drink. So I escorted her, made sure she got into the room safely, came back down to my post. Reporter: Does she look intoxicated on the tape to you? No. No. So, with that, he became my second suspect. Reporter: In fact, Perez would latered a Nate he'd be socializing with inn. I was friends with her in the workplace. I also had a friendship with her outside of the workplace. I thought very highly of her. Reporter: Given that Perez had a master key to all the rooms, the lead is promising. By now, one solid piece of evidence has emerged. DNA from the attacker was recovered from inna's body because she wasn't just beaten -- she was also raped. Samples are obtained from both the suspects. Which I voluntarily agreed to, without a problem. Also I don't afraid about that. Reporter: Now, possibly an even bigger break. Inna herself says she's begun to piece together memories of the attack, filling in the big blink between the elevator and the cul-de-sac, but only in fragments. What was she able to tell you about what had happened? Bits and pieces. I saw dreams, I saw nightmares. For me, it was very difficult to realize what was the reality, what was not the reality. Reporter: Now, she had a picture of the guys who had assaulted her. There were two white gentlemen, I don't think she could give me an age. They were either hispanic or european accents. I remember at least two other people. I don't remember the faces. I remember, like, a noise and I remember a person, like, putting like, a pillow or something. And then it's dark, you know, it's just like a feeling that you cannot breathe. Reporter: Inna even undergoes hypnosis to clarify her memories. She recalls being carried down a back staircase out into a car, driving somewhere and being raped in the back seat. I remember, like, somebody hits you all the time. I remember a laugh, somebody was laughing, at this point. Reporter: But for every promising lead, there are twice as many disorienting puzzles. For one thing, inn is certain she was attacked in her room. But that certainty just adds to detective Foote's headaches. I found it as a typical room, undisturbed. Reporter: No sign of a fight or assault? No. Bed's unmade, there were, you know, I found beer bottles, I found clothes hanging in the bathroom. But nothing to indicate that there had been any kind of a struggle. Reporter: As for inna's memory of being dragged down the back stairs, out an exit, and into a car? No dice. The exit door is covered by this security camera, which didn't capture anything like that. The camera's working properly, so, we reached a dead end on that point. It just didn't fit. Reporter: Detective Foote suspects there's more to inna's story than she's able or willing to tell. Aside from her hazy recollection, there's a big lingering question about her movements that night. Like many hotels, the airport regency has a key-card security system, which logs each time a guest swipes their key to enter a road. Now, here's the riddle -- the security cameras clock inn entering the elevator for the final time at 3:41. But the log of key swipes at her door shows her entering at 3:58. So, where was she then and what exactly could she have been doing? Those missing 17 minutes lead police to pursue another theory -- could inn be a prostitute? Maybe in that time she'd gone to meet a John in his room, perhaps that encounter lead to the attack. They didn't told me exactly, are you prostitute? All right? But the questions were, like, you know, if I ever had a sex for money and if -- this kind of question. It was emotionally difficult. Very, very, very difficult. Reporter: Police pursue that theory, but as the investigation proceeds -- I'm picking up absolutely zilch, nothing to indicate that she was a prostitute. Reporter: So, that left you kind of at a dead end at that point. Right. Reporter: For months, the case would remain a puzzle scattered in pieces. And to finally solve it, police would turn to an unlikely source, with an even more unlikeunlike unlikely theory. I could feel it.
This transcript has been automatically generated and may not be 100% accurate.