The FBI's controversial e-mail surveillance tool, known as Carnivore, can retrieve all communications that go through an Internet service

The FBI's controversial e-mail surveillance tool, known as Carnivore, can retrieve all communications that go through an Internet service — far more than FBI officials have said it does — a recent test of its potential sweep found, according to bureau documents. An FBI official involved with the test stressed Friday that although Carnivore has the ability to grab a large quantity of e-mails and Web communications, current law and specific court orders restrict its use. The Carnivore system, installed by the FBI on the network of Internet service providers, has software that scans Internet traffic as it moves through that provider's network. The FBI says it configures the software to capture e-mail to or from someone under investigation and that court orders limit which e-mails agents can see. Nevertheless, based on the new documents, privacy experts said they are worried about the breadth of Carnivore's capability and questioned why the FBI even conducted such a test in June if it intends to use the tool only for narrow purposes. "That really contradicts the explanation that the FBI has provided as to the purpose of the system and how it works," said David Sobel, general counsel for the Washington-based Electronic Privacy Information Center. In the lab report, FBI officials said Carnivore "could reliably capture and archive all unfiltered traffic to the internal hard drive" and could save the information on removable high-capacity disks as well. FBI officials say Carnivore has been used in about 25 cases, most involving national security.