Sacramento Police say someone in a realistic-looking  “cop car” pulled someone over and stole his wallet at gunpoint Tuesday, which begs the question, how do you know when a cop car is real?

Being able to recognize a phony cop cruiser is essential in a pinch.  The criminals in the robbery  pulled up behind the victim in an black Ford Crown Victoria, except this one had blue headlights,  tinted rear windows and a spotlight on the passenger side.  It sounds like a real  police you need to know what kind of lights to look for.

“Most people’s cars that represent to be police officer cars won’t have the flashing front clear lights, what we call wig-wags,” said Sacramento Police Sergeant Norm Leong.

It’s easy to get nervous when you see a car behind you, flashing lights and sounding a siren, but you don’t have to pull over immediately. “Call 9-1-1 and tell the dispatcher there’s a car behind you and you’re not sure if it’s a police officer, and you’re not going to stop until you get to a well-populated area,” said Leong.

And even if you think you`re sure about the lights, still be careful.  An auction house in Sacramento just sold half a dozen of old unmarked CHP cruisers.