Abstract: A method and apparatus for fraud control in cellular telephone systems. Call records from a switch are scanned to identify a fraudulent cellular phone based on its behavior. An identifier, e.g., a radio frequency (RF) signature, representative of the fraudulent phone is stored in a control channel editor at a cell site. A database of identifiers may comprise a positive validation database storing the identifiers for all valid phones used in the cellular telephone system, or it may be a negative validation database storing the identifiers for known fraudulent phones. A control channel editor intercepts a call origination request transmitted by a phone, and a control processor compares one or more characteristics of the phone transmitting the call origination request to the database of identifiers. The control processor then prevents the call origination request from completing when the comparison indicates that the phone is fraudulent.