Ok...maybe I was mistaken. I thought one of the press releases had stated that Gram had said they left at 11:30...and she saw them in the alley around 12:15. THEN the 12:15 was confirmed by LE with the camera footage so that is where they knew for SURE they were alive (12:15) so that was where the "start" of the timeline began.:banghead:
Either way - excluding Gram's statements - we KNOW they were on camera at 12:15 so it really doesn't matter when they left...heck it could have been 9am that morning that they left...they were alive at 12:15 for sure.
And assuming the bikes swerved around on the trail WERE the girls bikes that's still less than 15. That is very fast.