I think that Taylor's cell phone may hold some key piece of evidence. I have a daughter around Taylor and Skyla's age and I can say from first hand knowledge that when my daughter and her friends are all hanging out it never fails that someone will pull their cell and start taking pictures with it. What if Taylor and Skyla were goofing around with the phone and the killer/s thought that the girls may have taken their picture while doing something illegal? This is just something that came to mind when it was announced that the phone was being checked for TM's.
I would also think that LE would be able to pull call data info from the phone which might have been able to help pinpoint when the shootings happened.
IMO I think that the phone may be the key to helping to solve what happened to the girls.
MM ~