An independent reviewer of the FBI's controversial e-mail surveillance tool Carnivore says the system generally does not "overcollect" evidence — but his remarks failed to calm the fears of privacy advocates.

Henry H. Perritt, whose report on Carnivore was to be released Tuesday, said in an interview that he did recommend improvements to the system, both for efficiency and privacy, but that altogether it performed as advertised.

"I think that it's fair to say that it does pretty much what the FBI says it did. For the most part, it does not overcollect," he said Monday.

The release of Perritt's report, expected Tuesday night, has been delayed.

But some privacy watchdogs remained unconvinced by Perritt's conclusions.

"This finding, if it's true, still doesn't change the basic argument we're having about the standards under which Carnivore should be used," said Alan Davidson of the Washington-based Center for Democracy and Technology.

Perritt, who is dean of the Illinois Institute of Technology's Chicago-Kent College of Law, declined to list his recommended improvements or the ways Carnivore overcollects information.

The report is set to be released between 4 and 5 p.m. ET Tuesday and can be found on the Justice Department's Web site, usdoj.gov.

While the FBI steadfastly maintains that current laws and court orders restrict Carnivore from broad use, Davidson said wiretap law isn't keeping up with new gadgets.

"This sort of finding is in part why we've said a purely technical review of Carnivore's functions is not sufficient," he said. "Policy makers need a review that considers the law under which Carnivore operates and whether that law adequately protects privacy."

Congress considered several privacy bills during this past legislative term, including some specifically targeted at Carnivore. None of the bills survived, and legislators vowed to take up the issue again next year.

Carnivore was designed by the FBI to collect e-mail going to or from a suspect, in cases in which a suspect may be using electronic communications. Privacy experts have worried about the breadth of Carnivore's capability and its "black box" nature.

An FBI lab report released last week that said Carnivore "could reliably capture and archive all unfiltered traffic to the internal hard drive" alarmed many privacy advocates.

The FBI said the lab report was the result of a test to determine Carnivore's "breaking point," and that laws and court orders restricted Carnivore from being used so broadly. Privacy advocates, however, said the test showed that Carnivore was more powerful than the FBI had stated.

Controversial Review of a Controversial System

Justice Department spokeswoman Chris Watney said Monday that the Carnivore report was received last week in advance of Tuesday's planned release. The intervening days, she said, were needed to black out parts of the report that mention Carnivore's internal blueprints and other sensitive information.

Perritt added to Watney's comments that his recommendations for improving Carnivore will probably be held back as well.

Critics said the review would not be independent because the reviewers were government insiders appointed by Attorney General Janet Reno.

"This important issue deserves a truly independent review, not a whitewash," House Majority Leader Dick Armey, R-Texas, a longtime Carnivore opponent, said in October.

Perritt advised President Clinton's transition team on information policy and performing other tasks for the Clinton administration, as well as previous Republican administrations.

Associate Dean Harold J. Krent, another member of the team, worked at the Justice Department in the 1980s, and several team members have current or former security clearances from the Defense Department, Treasury Department or the National Security Agency.

Perritt said repeatedly he was completely independent and that his reputation would be damaged if he was anything but impartial.

Most of the nation's elite academic computer departments — including the Massachusetts Institute of Technology, Purdue University and the San Diego Supercomputer Center — either declined to review Carnivore or withdrew their applications after objecting to the requirements the Justice Department placed on the review.

The bureau says Carnivore has been used about 25 times, mostly in cases involving national security.

—  The Associated Press contributed to this report