Based upon the letters and calls we have received, your office undoubtedly has received many constituent inquiries about the "Carnivore" system. To help your staff respond to those inquiries, we are forwarding to you information about the legal requirements and technical aspects for using this court authorized technique. This seems especially important given the level of public misinformation and misunderstanding apparent from the inquiries we have received.

Law enforcement is experiencing what was inevitable. Just like everyone else, criminals and terrorists have turned to modern forms of computer communications to conduct their business and further their crimes. E-mail among criminals and terrorists is no longer unusual.

In 1968 and during the decades that followed, Congress carefully crafted a precise statutory scheme for intercepting communications. Essentially, law enforcement must demonstrate and a judge must conclude that there is probable cause to believe that a serious crime is being or has been committed; the communications (e-mails) sought are about or in furtherance of that crime; and that the interception is necessary to gather evidence about that crime. Intercepting the content of communications, even the "subject line" of e-mail, without meeting these standards and receiving an authorizing court order is itself a crime subject to severe criminal and civil sanctions.

The challenge then was how, when a court order is obtained, can FBI Agents or other officers intercept the content of e-mail going to or from a particular criminal when those communications are broken down into digital packets traveling with millions of other messages over the Internet.

That is what Carnivore does. When all the legal standards have been met and a judge authorizes, for example, the interception of e-mail from one drug dealer to another, this system, in conjunction with the necessary assistance of the appropriate Internet Service Provider (ISP), allows the interception of those particular e-mails to the exclusion of all others and all other types of computer traffic regardless of what it is or who sends or receives it.

Carnivore is only used in those small number of instances when an ISP cannot on its own deliver what the court order instructs and, for security and accountability reasons, the system has built in audit trails. The evidence produced by such court authorized intercepts traditionally is subject to vigorous challenge by defense lawyers and, of course, the process is supervised by the authorizing court.

In answer to the most common questions we are receiving, Carnivore is only used with the assistance of ISPs and is only connected while the authorizing order is in effect. It does not "snoop" through e-mail traveling through an ISP network by searching for key words or reading the "subject line" or any other content. That would be a crime. It only captures and then records the specific communications and/or addressing information specifically described in the order, e.g., e-mail between two criminals. It will be independently tested pursuant to a procedure established by the Department of Justice and we have shown the system to over 30 reporters and dozens on Capitol Hill. It unquestionably was ill-named.

Those of us in the law enforcement community appreciate the controversial nature of this subject and understand why it must receive careful and thoughtful scrutiny. Our primary concern remains that the public receive accurate information about Carnivore and its limited use by law enforcement to investigate, prosecute, and prevent very real risks to public safety and national security. Without capabilities like Carnivore, readily available technology can be easily employed by criminals and terrorists to defeat the ability of law enforcement to obtain crucial and timely evidence and to prevent serious crimes. We must continue to balance this crucial public safety need with the equally important need of preserving individual privacy. The FBI remains committed to helping maintain this balance.

If you or your staff need additional information, please do not hesitate to ask.

Sincerely yours,



John E. Collingwood
Assistant Director
Office of Public and
Congressional Affairs