The FBI's Carnivore e-mail snoop tool needs some fine-tuning to avoid unauthorized monitoring, but it is not powerful enough to pose a serious threat to the privacy of Americans, according to a draft study released late Tuesday by the Justice Department.

"Incorrectly configured, Carnivore can record any traffic it monitors," the study said. But the system "does not have nearly enough power" to collect and read all the e-mail that flows in and out of an Internet service provider.

The report, completed by the Illinois Institute of Technology Research Institute at Justice's request, includes recommendations to the FBI to make Carnivore more efficient, as well as ways to make the device easier for FBI agents to use.

The study also recommends that future versions of Carnivore be subjected to independent review.

The Justice Department censored several parts of the report before releasing it, including the system's technical blueprint. The report suggests eventually making the code public.

Henry H. Perritt, dean of the Illinois Institute of Technology's Chicago-Kent College of Law and head of the review team, said that in most cases Carnivore does not "overcollect" information beyond a court order and frequently is configured so that it doesn't collect as much data as is authorized.

Attorney General Janet Reno ordered the monthlong review, which cost the government more than $170,000, in response to fears that the government was overstepping its bounds to tap and confiscate e-mail correspondence.

Critics blasted the report. A civil rights lawyer said it presented nothing more than a "fuzzy snapshot" of the investigative tool. Others said its authors of harbored a bias for the government.

House Majority Leader Dick Armey, R-Texas, a longtime Carnivore critic, said the choice of the reviewers dictated the tone of the report.

"The Department of Justice selected reviewers and set the rules in order to ensure they would get the best possible review," Armey said in a statement Tuesday. "That makes this review questionable."

Perritt advised President Clinton's transition team on information policy in 1992 and performed other tasks for the Clinton administration. He worked also for previous Republican administrations.

Other members of his team have current or former security clearances from the Defense Department, Treasury Department or the National Security Agency, and one worked at the Justice Department in the 1980s.

Perritt shrugged off the allegations and insisted his team was independent.

"This is an old criticism," Perritt said in an interview Tuesday. "We had access to whatever we wanted."

"We had some actual court orders, and we talked to people in the field who used the system and grilled them on how they go about setting it up and deploying it," he said. "We had ample opportunity to find out how the thing is used."

"We found some reasons for concern and some further work" in the way the tool collects sender and recipient addresses in e-mail, Perritt said.

The FBI uses Carnivore under the same statutes that were written for telephone taps. Those laws don't always translate well, Perritt said: In a telephone trace order, authorities get the phone numbers of the caller and the person called; in an e-mail, there can be multiple recipients of the same message. This creates a legal conundrum.

Still, Perritt said, "The telephone wiretaps are a long-accepted tool of law enforcement and national security matters. The notion that because the Internet exists that we're not going to use those tools is ridiculous."

Barry Steinhardt, associate director of the American Civil Liberties Union, echoed Armey's statement.

"We continue to believe that this was not an independent study," Steinhardt said. "Most of the truly independent institutions declined to bid for the contract. In many respects, this is not just a snapshot, but a rather fuzzy snapshot of Carnivore."

He noted that Carnivore's technology is constantly evolving, so that new versions may have more sweeping capabilities.

Perritt is uneasy that the Justice Department may delete too much from his report.

"I hope they don't tear the guts out of this thing, because it's going to screw up their credibility and make life difficult for me," he said.

Perritt said the report is aimed calming the fears of people he says have an "exaggerated idea" of Carnivore's capabilities.

— The Associated Press contributed to this report