The main character is getting ready to start a job with the FBI or CIA or something and in the beginning he has a black crown vic, an old police cruiser, and they pull up by drug dealers who think they are cops and run, throwing their dope and money. So they pull up and get the dealers stuff and drive off.
I'm thinking the guy played in Species but I can't find his picture in the cast list. -- EDIT: NO HE WAS NOT ON SPECIES -- EDIT AGAIN -- I'm not entirely sure, it might have been the dude who was an astronaut and got infected with the Species and blew his head off and it grew back.
He had a bad drinking problem and became really violent and was prone to "go off the handle" for no real reason.