I heard on the radio this morning that a parked unmarked police cruiser, a Dodge Charger, was stolen from Detroit, ironically, from a policeman who was with the auto theft unit. Later, a woman who's car had stalled out on I-94 was raped by two men who drove up in a vehicle that matched the description. The wire story is here.
The stolen car's license plate is 8JP H46.
If you are ever followed by a vehicle that looks like a police car, but is not marked, you are NOT obligated to pull over. If they flash lights at you, and you aren't sure if they are legit or not, do not pull over unless you are in a well lit public area. You can also call 911 and explain what is going on, and they will try figure out what is going on.