Got into an accident with a cop car?

was it your fault or the cops?

If it was your fault and you know it, be honest and own up to it.

A Police officer has greater resources to bring you to justice than other drivers.

If it was the cops fault, have as many witnesses as possible and get pictures.

If he is an honest cop, you should have no problem, if he isn't, you may have a long fight on your hands.