Do cops ever shoot radar to the back of their car?

same thing happened to me and no they dont turn around in their seat they have radars attached to their windows that tracks speed of cars coming behind them i got pulled over by a cop driving a dodge charger who was parked tha same way you said and she had a big radar gun on her back driver side window and she said i was goin 59 in a 40 (even though my spedometer said 49) but she let me off with a warning...but ya its on their window...and next time ur radar detector goes off u should slow down cuz thats y ppl like us have them..to get us out of speeding tickets lol too bad i didnt have mine tha day i got pulled over or i would have known tha cop was parked over tha hill b4 i got there haha