In January 2008, the ACLU received documents from the Central Intelligence Agency revealing that the agency has secretly issued National Security Letters (NSLs) to obtain sensitive financial records about people in the U.S. without any court approval.

The documents show that the CIA used heavy-handed secrecy tactics to gag NSL recipients and prevent them from talking about the fact that the CIA demanded information from them. Unlike other agencies that issue NSLs and gag NSL recipients, the CIA appears to have required NSL recipients to sign non-disclosure or gag agreements acknowledging that they were gagged and could not disclose the existence of the NSL to anyone, and then return the signed form to the CIA. The documents also suggest that the CIA often would not even let the NSL recipient keep a copy of the letter — the CIA would take it back and keep it in the agency's files. Some of the NSLs go so far as to ask that recipients not maintain any records that “evidence the details” of the NSL.