Instrumentalities of crime:
Before a judge or magistrate may issue a search warrant, there must be a finding of probable cause. The level of evidence required to demonstrate probable cause is greater than "mere suspicion," but is less than the level required for a criminal conviction (beyond a reasonable doubt). The facts must demonstrate that a reasonable person would believe that the location, which is the subject of the warrant contains evidence of a crime, the instrumentalities of a crime (e.g., safe-cracking equipment), contraband (e.g., illegal materials such as drugs), or the fruits of a crime (e.g., stolen property). See
EXAMPLE (1): Officer Tropvite has seen Joe lurking around the back of a store nearby his home and suspects that Joe plans to rob the store. Although the Officer has no reason to believe that any instrumentalities of crime exist at Joe’s house, he asks Judge Prudent for a search warrant, hoping that the search might scare Joe off from the possible future crime. Without some evidence from which a reasonably prudent person could conclude that tools to be used in the crime would be found in Joe's house, Judge Prudent should not issue the warrant.
EXAMPLE (2): Not to be discouraged from capturing Joe and winning county-wide acclaim, Officer Tropvite follows Joe around for a few days. Over that period of time he observes (and documents) Joe purchasing a large pair of bolt cutters, a black ski mask, leather gloves, a ladder, and 2 large duffel bags. He watches Joe transfer these items from his car to his garage. Returning to Judge Prudent with this new evidence, Officer Tropvite will likely be granted his request for a search warrant for Joe’s garage.
Probable cause may be demonstrated by live, sworn testimony or by affidavit. More importantly, an affidavit based on hearsay (which could not be used as evidence in a criminal trial) can be used as the basis for issuing a search warrant, so long as the circumstances in their totality establish probable cause. See