hmmm....so I just checked out her myspace page.
The fact that Jenni-Lyn was as accomplished as she was in dance (has performed with the Moscow Ballet!), tells me that she's worked VERY hard for a VERY long time. Dancers at that level generally began spending many many hours a week at a very young age. By the time they get into their teens, the majority of their time outside of school is spent focusing on dance - not much time for dating and socializing.
It is very clear from her myspace page, that the boyfriend (ex-fiance?) was a "first love". Almost EVERY single picture is of the two of them kissing. There are no pictures of Jenni-Lyn with girlfriends or family members. Which leads me to believe that she was pretty infatuated with having a boyfriend, and not focusing on much else.
All too often, this type of head-over-heels infatuation leads to very possesive feelings towards each other. Especially if it was the "first love" for both of them.
If he wasn't really on any path towards goals as she was, he may have become very possesive, and if her family and friends didn't really agree with their relationship - it could very possibly have led to her isolating herself from them in favor of keeping him happy.
If I was her parents and my daughter had such amazing talent and had already accomplished so much, I wouldn't love seeing pictures of her in her bed making out with him at college. That means he's going to visit her and taking her away from other things like, dance, her studies, and the opportunity to enjoy new friends and activities at college.
Since her myspace page was published with all the pics of them - she's created her FB page and clearly started to incorporate more people in her life. The fact that he had already asked her to marry him indicates that he knew very well that she was quite a catch. It also put a claim on her finger which means that all of the decisions she makes about her future are supposed to include him. She's verrrry young for that.
It seems that she finally came to her senses and called it off (phew!). But again, he was CLEARLY infatuated and really may have flipped his lid.
He may have had NO idea how to handle the rejection - he wanted her with him for life and he thought he had it.
The one thing I'll say is this - unless he has a violent history, I find it unlikely that he would have ended her life, even by accident.
If he does have her with him, I think he's just begging and pleading for her not to leave him. He may even be threatening to kill himself if she won't change her mind. If this is the first time she's ever dealt with this kind of emotional assault, he might be making her feel horrible with guilt. The thing is, when someone with no violent history snaps over a break-up, what they want MOST is the other person to BE with them - so killing that person would defeat their purpose. He may very well have harmed her, maybe even badly, but I don't think he'd kill her and hide her body.
If he does have her, and she's alive, its possible that they're both scared to death because its gotten so blown out in the open. She might feel very worried that he's going to get into trouble, and she might feel very guilty. I think LE already knows that she's alive and that she's with him - they're just trying to "talk him off a ledge" and get her back safely.
Now if it comes out that he's have a violent history, history of mental illness or instability, or drug/alcohol abuse - that changes things. Those factors make it much more likely that he may have taken her life.