There are various guidelines in place for police officers who wish to obtain a warrant to inspect a person's home or car. These guidelines are in place to protect the general public from unlawful searches and seizures.
Most people are aware they can ask police officers for a warrant when they demand to enter a private residence. However, there are some occasions when a warrant is not necessary. For instance, if an officer asked to peruse a person's home and that person granted permission, then lack of a warrant would not matter if the officer later found an illegal substance. Here are other times when officers do not legally need warrants:
An illegal item is in plain view
The police could seize an item and arrest a person as long as the item is in plain view. This means an officer can plainly see the item from outside the premises, usually through a window. A police officer would ordinarily be unable to search a person's vehicle without probable cause. However, if the officer could see a bag of marijuana through the window, then a full search would be within her or his rights.
Exigent circumstances exist
Exigent circumstances refer to times when an officer believes a suspect is destroying evidence or evading capture. In the event an officer wanted to search a person's house for drugs and immediately hears flushing, then she or he would be within her or his rights to break down a door. The same rule applies if an officer hears of a domestic dispute at a home. A warrant is unnecessary because the police need to protect someone from potential harm.
Performing a protective sweep
When police officers arrest someone in a house, they can legally search the rest of the premises to locate evidence or accomplices. Police can add extra charges if they find drugs or other types of illegal paraphernalia in a house, even if such items have nothing to do with the initial arrest.