California Code, Penal Code - PEN § 633

(a) Nothing in Section 631, 632, 632.5, 632.6, or 632.7 prohibits the Attorney General, any district attorney, or any assistant, deputy, or investigator of the Attorney General or any district attorney, any officer of the California Highway Patrol, any peace officer of the Office of Internal Affairs of the Department of Corrections and Rehabilitation, any chief of police, assistant chief of police, or police officer of a city or city and county, any sheriff, undersheriff, or deputy sheriff regularly employed and paid in that capacity by a county, police officer of the County of Los Angeles, or any person acting pursuant to the direction of one of these law enforcement officers acting within the scope of his or her authority, from overhearing or recording any communication that they could lawfully overhear or record prior to January 1, 1968.

(b) Nothing in Section 631, 632, 632.5, 632.6, or 632.7 renders inadmissible any evidence obtained by the above-named persons by means of overhearing or recording any communication that they could lawfully overhear or record prior to January 1, 1968.