Latest theory, supported by photos: Jenner's SUV initiated the crash and actually hit both cars. Prius was slowed or stopped in traffic for a light further down the road. The Lexus was also stopped. Jenner's SUV tries to avoid a collision by veering to the right, but strikes the Lexus, causing it to carom to the left into oncoming traffic. The SUV continues to move forward and strikes the rear of the Prius.
The Prius owner's lawyer claims the impression of the Escalade's emblem is visible on the Prius. The rear damage to the Prius is consistent with being hit by the Escalade.
If the above proves to be correct, then Jenner is responsible for the accident, the death, and subject to prosecution.
Link:
Bruce Jenner -- Car Crash Photos Could Create Problems for Jenner | TMZ.com