I Come in Peace?
No, but I'm glad you reminded me of that one. Haven't seen it in years. That's the Dolph Lundgren one where he shoots those disc things.
This one wasn't so much about cop stuff (like drug trafficking and such). I think the only reason for the cop angle was because the supporting role was a cop investigating some murders done by the bad guy alien and couldn't really piece it all together. The connection was that the bad guy was going from body to body and didn't care what happened to him each time because he could just use someone else. So the crimes seemed entirely random and were committed by people who didn't fit any kind of profile (since they were being possessed).
The good guy alien was posing as a human cop to try and track down the bad guy, but I think there was some history of how he got into that body or something. Maybe it was a cop who was hurt when the aliens got there, or maybe that body wasn't a cop but took the identity of a cop who was killed, something to that effect.