I've seen several comments about MT - that she's in a stable relationship, she's a great, caring girl, and she's committed to her BF. And I think she probably is. But - she is 20. I remember back to being a 20 yr old girl - good, caring, and committed to my BF. At 20, or even 40 or 60, nice, caring, good people can find themselves questioning their relationships. Sometimes, someone will come along and provide an emotional need you may not be getting from your committed relationship. That doesn't mean you don't still feel those things for your BF, but you can find yourself in a very confusing situation.
I think it's possible that MT was in this particular situation. Maybe she was infatuated with someone else. Maybe she just enjoyed the attention she was receiving from someone. I have no idea if this is the case, but I do think she could have talked to this person every day and he would have known her schedule or plans for the evening. If he showed up at her house or during her jog and asked her to go with him, I doubt she would have reservations getting in a car with him.
He could have appeared to be a perfectly normal person, but his outside appearance could have hidden a monster. You see this in many murders - newlyweds and long married couples have found themselves in these situations.
I was sure she was alive in the beginning, but I have lost hope for that outcome. I hope they find her soon. JMO