Police involved car crash - What are they hiding ?

I came upon an major accident which involved a police vehicle, but when I got there the only piece missing was the cop car that was involved in this MAJOR car crash....wonder why ? Looking into this a little, things do not add up. I did see a short video of the damage to the cop car. The cop car had major damage to the back. There were 3 other cars with back end damage and only one car had front damage. 3 cars ( including the cop car ) had so much damage they will be totaled. So, the cop had to have rear ended the one car that has major rear damage because the car that has front end damage had to have hit the cop. With all the damage, the cop had to have been traveling over the speed limit and may have caused this mess. Maybe that is why they will not talk about why the cop car is missing from this accident minutes after it happened. As you see, there are doing a major investigation of this incident, but the only problem is, the major player is missing from the investigation ??!? I cant wait to do some FIOA requests to see how they spin this one.