New York City police are piecing together the last moments of a murdered graduate student's life. Imette St. Guillen would have celebrated her 25th birthday on Thursday. Here is an edited version of FNC's Brigette Quinn's interview with former Miami Beach Detective Joe Matthews, an investigator for "America's Most Wanted."

Does it sound to you like somebody happened upon this girl after she left the bar? Is there still the possibility that she met somebody inside that last bar that she was seen in, and that she left with that person? My understanding is there's no surveillance camera outside that particular bar, so you would have to go by witness accounts whether she left alone or not?

Matthews: In an investigation like this, the New York City Police are looking in every single aspect of it. They are doing a complete background on her to see if maybe she met someone there and he didn't want her girlfriend to know she was meeting someone at another bar later the night.

It could have happened inside. I know that they are checking their credit cards because from what I understand, she paid for some drinks at one of the bars she attended. Now, was she drinking at the third bar and did she pay for those drinks or did somebody pay for them? Of course, the other thing could be if somebody just abducted her off the street.

There's some speculation that maybe she took a ride home from somebody who posed as person trying to help her, but then wound up hurting her. What do you think about that theory?

Matthews: Well, the way you are going to determine that by looking at her pattern of behavior. You have to interview all her friends now and back at home. Is she the type of person who would look for a cab or try to go to a subway? Would she be someone that if somebody be befriended her she would go home with them? Does her behavior change when she is intoxicated?

From what you read about this case and been looking at in this case, does it seem to you like this was a random attack?

Matthews: You know, you can't have tunnel vision in this. Sometimes the suspect wants you to believe one thing and it is totally different. Unnecessary things are done so you wouldn't investigate a certain person. You would say "oh, this is a random killing." But in fact, maybe it was someone that possibly knew her or had contact with her. From what I understand, she was going for her Master's degree in forensic psychology.

What the police are doing now is they are going back on work programs that she was involved with, maybe she interviewed someone there that was attracted to her and stalked her. Or this could have been a random abduction.

Do you think the person who called 911 to report the body found could be the killer?

Matthews: That's the likelihood that it probably was. Why did he report it? Number one, do people think there was remorse, he wanted to find this abandoned body? Or number two, did he get excited knowing the media would get on and it is like an arson. The bigger the fire the more excited he was.