FBI Seal Frequently Asked Questions


What is a National Security Letter?

A National Security Letter (NSL) is a letter request for information from a third party that is issued by the FBI or by other government agencies with authority to conduct national security investigations.

What statutes provide NSL authority?

NSL authority is provided by five provisions of law:

How valuable are NSLs?

In the post 9/11 world, the National Security Letter is an indispensable tool and building block of an investigation that contributes significantly to the FBI’s ability to carry out its national security responsibilities by directly supporting the furtherance of the counterterrorism, counterintelligence and intelligence missions.

How are NSLs different from subpoenas? Are NSLs subject to limitations?

Why not just use subpoenas?

There are multiple benefits of NSLS over grand jury subpoenas:

  1. NSLs are less intrusive in contrast to other tools such as FISAs, and provide a means to obtain third-party information relevant to a national security investigation.
  2. NSLs can also be issued before an investigation is opened in a grand jury by a U.S. Attorney’s Office but must be relevant to an authorized FBI national security investigation.
  3. Although the non-disclosure provisions in NSLs no longer automatically attach, NSLs are a better investigative tool should the government decide that non-disclosure of the request is necessary on a long-term basis due to the sensitivity of the investigation and the potential harm from an NSL’s disclosure.

What types of transactional information may be obtained by an NSL?

The FBI may obtain the following transactional records:

How are NSLs certified?

All NSLs require a certification that the records sought are relevant to an authorized investigation to protect against international terrorism or clandestine intelligence activities and that an investigation of a US person is not conducted solely on the basis of First Amendment activities.

Can a provider challenge an NSL?

Yes. All recipients have the right to challenge, in U.S. District Court, a NSL for which the recipient believes compliance would be either “unreasonable, oppressive, or otherwise.” The recipient may also challenge, in U.S. District Court, any applicable nondisclosure provisions. In other words, unless the Court finds certification in bad faith, the law leaves these determinations regarding U.S. national security and diplomatic relations to the Executive Branch.

Who is authorized to approve NSLs?

Are NSLs classified?

The NSLs themselves are not classified, nor is the material received in return from NSLs classified. That information may be used in criminal proceedings without any declassification issue.


Source: FBI