I've often thought about this scenario.  Never open the door to police no matter what they say.  They can only come in with a warrant.  If they have a warrant they will bust your door down anyways.  I once heard a lawyer say, to never talk to the police under any circumstances.  Never.. Nothing good comes from it.  It can only harm you.  The police can make mistakes our you could unintentionally incriminate yourself.  I.e. Police comes to your door, you answer and say what? Did someone get hurt?  Cop says, what do you mean, I never said anything about  that?  Now Pandora a box is open.  Interesting thought.  If you wanted to open the door ask them to go back and flash their emergency lights on their cars.  Red and blue.