Auto Insurance Claims: Auto Accident, independent investigations, insurance investigator

Question
Hi Webfoot,
I was rear ended by a drunk driver on the way to work. (friday).  I called this guys insurance on Sunday to file a claim.  I got a return call on Monday from the Insurance company who says she was doing an "Invesigation" and that the facts given by me were different then that of their insured. (go figure!)
Who determines fault? Me? the Highway Patrol? The Insurance "Investigator"?
This guy was taken away in handcuffs, and I have to convince someone that he was at fault??

Answer
The Highway patrol and both of the insurance companies will conduct independent investigations.  The fact that the guy was taken away in handcuffs has absolutely nothing to do with the mechanics of the accident and an insurer has a legal obligation to conduct a complete investigation including taking the statements of all involved parties, inspecting the involved vehicles, interviewing witnesses, reviewing the police report and sometimes conducting a scene investigation before making a liability decision.  

If you are unwilling to wait through this process you are free to file a collision claim with your own carrier and then let them deal with the investigation.  It's either wait or file a claim.