Under the “collective knowledge” doctrine, where one officer involved in a criminal investigation knows facts constituting reasonable suspicion or probable cause sufficient to justify an action under an exception to the warrant requirement of the 4th Amendment, and he communicates an appropriate order or request, another officer may conduct a warrantless stop, search or arrest without violating the 4th Amendment even though the arresting officer, himself, does not possess the knowledge. Here a team of Glendale officers investigating narcotics violations developed probable cause sufficient to justify a detention and search. They requested a second officer, not involved in the investigation, to conduct a traffic stop which he did. Following the stop, the vehicle was searched and the narcotics were located. The search was justified by probable cause arising from the collective knowledge of the officers involved.