In People v. Brandow (1970) 12 Cal.App.3d 749, a police officer furnished a prostitute with a tape recorder after she agreed to help police in a crackdown on criminal pandering, pimping and prostitution. The prostitute recorded conversations of various individuals who called her using her private unlisted telephone line. The police officer visited the prostitute almost daily, and reviewed with her the contents of the tape recordings and the activities since the last visit. (Brandow, supra, 12 Cal.App.3d at p. 752.) The prostitute recorded conversations with approximately 60 different people and obtained identifiable tapes of approximately 45 different persons, including the defendant. The prostitute testified at trial, and the tape recordings were played to the jury. On appeal, the Brandow court rejected the defendant's claim the surreptitious tape recordings constituted an illegal search, citing Hoffa, supra, 385 U.S. 293, and other Supreme Court decisions. (Brandow, supra, at p. 753.) The Brandow court also noted the recordings were properly admissible as corroborating the prostitute's testimony under the "well established" rule that a conversation may be monitored when one person to the conversation consents. (Ibid.)