When the police come to your door in Fairfax or anywhere else, tell them not to come in without a warrant. Police need a search warrant to enter you home unless you invite them in.
Do not stand aside just because it is the police. It is your home and the police have no right to enter your home without your permission.
There is an exception to the warrant requirement, called "exigent circumstances," when the police have reason to believe that someone whom they have been hotly pursuing [as in chasing] is in your home or if the police have reason to believe that you are about to flush away or otherwise destroy evidence of a crime or if the police are investigating a recently received 911 call regarding an allegation of domestic assault. Even in these circumstances, your lawyer should contest any evidence acquired by the police in your home when they did not have a warrant to enter.