The way I see it, there are three options
1) BM did it
2) JL did it, or arranged for someone to do it
3)A third party did it, not pre planned by JL and she is a victim
For JL to identify BM it rules out 3, as if he really didn't do it and someone else did it, then she has no reason to identify him falsely. It only makes sense her IDing him if he really did it, or if she's hiding something else.
I honestly don't know what to think. It does worry me when they say JL didn't behave "normally". If a woman doesn't cry or get upset when a crime has taken place, they are judged more harshly IMHO. We don't automatically assume a male is guilty if he doesn't cry. Who can say how any of us would react if something like this happened?
On the other hand, the police are trained to interview suspects. They have spoken to many over the years. I feel their suspicions, that something is off when they are interviewing someone, is generally more believable than the general public because they have that exposure to more people in these situations.