Which case defines the fellow officer rule (collective knowledge of police)?

• A. Freeman v. State
• B. United States v. Hensley
• C. Graham v. Connor
• D. Hoffa v. United States

Answer: (B)

The fellow officer rule, or collective knowledge doctrine, allows information known by one officer to count toward probable cause or reasonable suspicion for another officer’s action. This reflects how police work unfolds across multiple officers and units, so the total knowledge shared among them can justify a stop or arrest even if the executing officer didn’t witness the initial facts firsthand.

United States v. Hensley explicitly defines this rule. In that decision, the Court held that information supplied by one officer—if it describes a suspect with sufficient detail and is timely enough—can be used to justify a stop or action by other officers who act on that information. The idea is that the police are a team, and their combined knowledge can create probable cause, as long as the description is reliable and the connection to the suspect is appropriate in time and place.

That makes United States v. Hensley the correct reference for this concept. The other cases address different Fourth Amendment issues and do not establish the fellow officer rule in the same way.