When are the police allowed to enter my home or business?

When are the police allowed to enter my home or business?

There's an old adage here in the United States that a man is king of his castle. And there's still an old Wild West element that nobody is allowed to enter your house without your permission or without a search warrant. And a search warrant is when a judge or a magistrate signs a piece of paper saying that there is probable cause to believe a crime has been committed there. The only exception is what we call exigent circumstances or where there's an emergency such as somebody screaming for help or gunshots behind the door, that obviously not only common sense, but the law would dictate that the police can enter.