I'm kinda of surprised this is not already posted. In a case from Kentucky; police where chasing a drug suspect into an apartment complex, and lost sight of the suspect. In searching the complex they come to a door and smelled marijuana. They knocked and announced, though they heard evidence being destroyed; busted down the door. The supreme court 8-1 said this is ok. Supreme Court allows warrantless drug search in Kentucky case - Louisville Public Policy | Examiner.com I personally thinks this goes way beyond drugs. Now if the cops what to search your home it is an easy 3 step process: 1) Knock and announce. 2) Wait a second or two and hear something that might be destroying evidence. This could be a flushing of a toilet, typing on a keyboard, paper shredder. 3) Bust down your door. 4) Well OK here is number 4. Make up a reason after word. I have no problem with the police, most of them are top notch people who do a very hard job; and get very little in thanks. So if your a cop, thanks for what you do for us. The state, including the police have great power, and the bill of rights was setup to protect the people from that power. The fourth and fifth amendments are not to protect the guilty, they are to protect the innocent.