AT&T employees work alongside the DEA and local law enforcement agencies at High Intensity Drug Trafficking Area offices in Los Angeles, Atlanta, Dallas and Houston, where they supply officials with metadata from a database of telephone calls dating back to 1987. The information is handed over in response to subpoenas, rather than search warrants. The DEA has the power to issue "administrative subpoenas" without involvement of a court. Call detail records are collected for all calls handled by AT&T's switches, not only calls placed by AT&T customers. The records include the caller's location and number around four billion per day. A telephone call may create more than one entry in the database.