thats already happened many times.  example 1 -There was a man in west Denver about 7 years ago killed in bed drinking a diet pepsi - the cop saw the flash of metal and shot.  
Wrong guy wrong house innocent murdered no charges.
Also the woman who was assaulted by police at a hospital after bringing her boyfriend who had been shot - they were the victims but because the car had been "involved" (shot at) she was suddenly a criminal who deserved to be kicked and have her head stomped on.