Both 16mm and 35mm surveillance cameras are used in banks as an integral part of bank security systems. They are used to record the transactions occurring in banks every day and to aid police following a holdup. Cameras mounted at tellers' stations aid in tracing fraudulent check passers. Tellers are urged to follow a robber's directions exactly during a holdup and, when it is safe, to activate the security alarms. The immediate crime scene should be protected to preserve fingerprints and other evidence needed by the police. Surveillance cameras can deter crime, aid police in getting a positive identification of the robber, and increase the conviction rate.