collective knowledge
Collective knowledge, also known as the “fellow officer” rule, is a criminal law principle that allows police officers to share and rely on information from other officers. Under this doctrine, individual officers can act on shared information from other officers even though they do not have direct knowledge themselves. According to Whiteley v. Warden, 401 U.S. 560 (1971), an officer can search or arrest a suspect if informed of probable cause by another officer without independently verifying the details. The communicating officer with probable cause must provide sufficient information to the acting officer in order to avoid violating Fourth Amendment protections against unreasonable searches. For example, one officer witnesses an illegal activity and relays the information about the suspect over the radio. A second officer, who did not witness the crime, receives the information and identifies the suspect. The second officer may act by stopping and searching the suspect based on the collective knowledge/fellow officer rule. This doctrine may also be used to relay information during vehicle pursuits. See: United States v. Ramirez, 473 F.3d 1026 (9th Cir. 2007).
[Last reviewed in March of 2026 by the Wex Definitions Team]
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