School officials, including police who assist in maintaining general order on school campuses, need not articulate a specific crime which appears to be violated in order to detain an outsider for the limited purpose of determining the fundamental factors justifying the outsider’s presence on a school campus. Moreover, the right to detain is not confined to school hours. Here, Salas, a uniformed police officer assigned to the school district, acted on the request of school official Fink in detaining appellant. Salas did not need actual knowledge to detain appellant pursuant to Fink’s request. Here, the detention was reasonably necessary to determine whether appellant was properly on school grounds. Accordingly, there was sufficient evidence to conclude that Salas was acting lawfully in the performance of his duties, an element of the offense of battery on and resisting a police officer in violation of Penal Code section 243, subdivision (b), or section 148, subdivision (a).