The Fourth Amendment to the U.S. Constitution establishes that law enforcement officers may only search people and property when it is legally reasonable to do so. The law generally requires police to get a search warrant from a judge before seeking evidence from a vehicle or private property. A few factors, such as consent, emergencies and evidence in plain view, allow police to perform searches without warrants, but evidence collected might become illegitimate if they cross legal lines.

Limitations on consenting to police searches

Even a person who consents to a police search is not necessarily giving police broad permission to search everywhere. If police request to search a garage and a person gives permission, then law enforcement may legally search the garage but not other buildings on the property unless they obtain additional consent. When police want to search a vehicle during a traffic stop or even a person’s body, they can only proceed without consent or a warrant when reasonable suspicion exists that doing so will uncover evidence of a crime.

When a search is illegal

Violations of these rules might prevent the use of any evidence obtained by the illegal search against a defendant. A search that is deemed illegal could justify excluding the evidence from the case. If evidence taken during an illegal search leads to the discovery of more evidence, then that secondary evidence may also be excluded under the “fruit of the poisonous tree” doctrine.

Part of the services provided by a criminal defense attorney might involve examining the legality of searches. Any signs of misconduct by law enforcement may empower an attorney to ask for evidence to be excluded. Beyond confirming the legitimacy of the evidence, an attorney might also help a defendant decide how to enter a plea or negotiate a reduction of charges.