The Nov. 6 front-page article "The FBI's Secret Scrutiny; in Hunt for Terrorists, Bureau Examines Records of Ordinary Americans" was a misleading portrayal of the FBI's use of national security letters, an important tool for preventing terrorist attacks and espionage.

Contrary to the impression left by Barton Gellman's article, national security letters do not allow the FBI to spy on ordinary Americans, to listen in on phone calls or to read e-mails. They do allow the FBI to check leads and request specific categories of information critical in tracking the activities of terrorists and spies.

These letters, like subpoenas, are simply requests for information. If a recipient refuses to produce the information, only a court can compel compliance. Moreover, the recipient may go to court to challenge the letter. When some contended that this right to challenge a letter was unclear, the Justice Department supported amendments to make it explicit.

Statutes limit what information may be requested and from whom. The letters may be used, for example, to request credit card records, but they may not be used to obtain e-mail contents or library checkout records.

Most important, national security letters cannot be used to investigate ordinary crimes or even domestic terrorism; they are limited to requests for information relevant to international terrorism and espionage investigations. The law does require the recipient of a letter not to disclose that he or she received one because confidentiality is essential to success in these investigations.

The Justice Department is committed to protecting civil liberties and to using all investigative tools judiciously and within the bounds of the law. This includes national security letters, one of the important tools Congress provided to help us secure our nation.

RACHEL BRAND

Assistant Attorney General

Office of Legal Policy

U.S. Department of Justice

JOHN PISTOLE

Deputy Director

Federal Bureau of Investigation

Washington