What is probable cause?

Probable cause basically boils down to a “reasonable belief” that a crime has been committed or that evidence of a crime exists at the place being searched or that a suspect has committed a crime. Because a “reasonable belief” is a relatively fluid concept, probable cause determinations are based, in part, on a magistrate’s common sense as applied to the totality of the circumstances. In other words, given all the circumstances set forth in the affidavit for a warrant, including the truthfulness, credibility, and basis of knowledge of the persons supplying information, the test is whether there is a fair probability that contraband or evidence of a crime will be found in a particular place or that a suspect committed a crime.