[onetwo_threefour]

As a lawyer who used to do personal injury (until the soft cap got passed in 2004) I would agree with the consensus here that the cop's conduct is questionable, are you sure it was really a cop and not someone pretending to be one? I can't see the police laying charges for filing a false report unless there is clear and unambiguous evidence. It's a difficult charge to prove.

As far as the witnesses go, someone in your car is not necessarily a bad witness, especially since they can speak to both the circumstances of the accident (including your driving) as well as the pre-existing condition of the vehicle. If a judge feels that the person is believable in Court then there is no reason that there testimony wouldn't carry significant weight.

Finally, yes do report to your insurer and let them run with the damage claim. You migh also consider tracking down any independent persons who have recently had an opportunity to look at the back end of your car, such as a gas station attendant you see all the time, your neighbour across the street who sees your car everyday, the guy in your carpool, or whatever, and ask them if they would be willing to write a brief statement saying that they did not see any pre-existing damage despite seeing your car on a regular basis.

Realistically, you shouldn't need a lawyer, but if your insurer starts considering apportioning liability you may want to get a legal opinion. Ultimately, your insurance company has a pretty broad power to determine liability without your say so, but you can challenge sucha decision via the insurer's internal appeals process, through the insurance ombudsman, or, if all else fails through Court on an argument that your insurer has breached its duty to defend you.

Good luck....