I am a field technician, so I'm driving all day. In my experience (even before I was a technician), cops can be some of the worst drivers on the road. I don't know if some municipalities cut corners by not optioning squad cars with turn signals, but I am honestly amazed when I see an officer use one. Many times I see squad cars weave in and out of traffic without lights or sirens (or turn signals!!!). Or the ever-amusing flipping on the lights when he/she doesn't want to wait at a red light-- making cross-traffic slam on the brakes or swerve, only to turn them off when he/she clears the intersection. Many times the badge = powertrip and/or immunity to proper driving rules.
Sounds to me like the officer in your story fukked up and is trying to intimidate you (along with his gang of cop-buddies) into taking the blame because he doesn't want to deal with the results. I'm not suprised one bit. If you have even one witness who will back you up, he's screwed big time for knowingly filing a false report. Probably desk-jockey duty for a while, if not termination. He's almost better off just fessing up to hitting you if you think about it.
Good luck... I hate when people get screwed over by other people taking advantage of their position.