WASHINGTON - A federal judge said yesterday that he is not convinced that allowing a lawsuit by Dr. Steven J. Hatfill to proceed will endanger the FBI's investigation of the anthrax letters that killed five people in 2001.

During a motions hearing, U.S. District Judge Reggie B. Walton expressed sympathy for Hatfill's claim that government leaks have wrecked his career, the basis for the suit he filed in August against Attorney General John Ashcroft, the Justice Department, the FBI and other law enforcement officials.

"I totally understand how his life has been, at least at this point, virtually destroyed," Walton said. "I know I'm not inclined to give an open-ended stay," which would freeze the lawsuit indefinitely.

Walton said the government's voluminous court filings have not persuaded him to postpone the suit until the anthrax case is solved, as Justice Department lawyers are seeking.

"Is Mr. Hatfill still a suspect?" Walton asked. "Are there any suspects? At some point, it seems to me, if Mr. Hatfill did not commit this crime, he should get his life back."

In response, Assistant U.S. Attorney Mark E. Nagle told the judge that later yesterday the Justice Department would deliver to him an affidavit containing secret additional information on the progress of the anthrax case to justify the delay.

Nagle called Hatfill "an individual who by his own declaration is implicated in the investigation" but gave no indication of whether investigators still are interested in the former Army biowarfare expert.

Hatfill, 50, who worked as a virologist at the Army's biodefense laboratory at Fort Detrick from 1997 to 1999, was the focus of an international tidal wave of publicity after the FBI first searched his Frederick apartment in June 2002. Investigators also searched his girlfriend's apartment in Washington and a storage locker he had rented in Florida.

For much of 2002 and 2003, FBI surveillance teams kept Hatfill under 24-hour watch, and one FBI watcher actually ran over Hatfill's foot after the scientist approached his car outside a Georgetown paint store. In three nationally broadcast television appearances, Ashcroft called Hatfill a "person of interest" in the anthrax case.

Since coming under scrutiny in the anthrax case, Hatfill has been fired from jobs as a bioterrorism trainer at defense contractor Science Applications International Corp. and at Louisiana State University, which was formally advised by the Justice Department not to employ him on federal contracts.

In researching hundreds of articles and broadcasts about Hatfill, reporters have discovered that he claimed to hold a Ph.D. he did not earn and used a forged Ph.D. certificate from a South African university to get research jobs at the National Institutes of Health and at Fort Detrick. Acquaintances have described Hatfill as a colorful and eccentric character who explained and sometimes demonstrated how terrorists could cook up bioweapons in kitchen labs and once posed for a magazine photographer in an improvised biohazard suit.

But FBI investigators have never made public evidence linking Hatfill to the anthrax attacks. Law enforcement sources told The Sun last year that the investigators were divided over whether the pursuit of Hatfill showed promise or was a distraction and waste of resources

For his part, Hatfill has consistently denied that he had anything to do with the anthrax attacks, which shut down federal and congressional offices and sickened at least 17 people in addition to the five killed. In public statements and in his lawsuit, he asserts that the government has made him a scapegoat for its failure to find the real culprit who mailed anthrax-laced letters to news media organizations and two U.S. senators in late 2001.

Hatfill now lives with his girlfriend in Washington and has been unable to find work, his lawyers and friends say. They also say the FBI surveillance that was obvious until late last year has become far less evident or has been dropped.

Mark A. Grannis, who represented Hatfill yesterday along with Thomas G. Connolly, said his client has a right under the federal Privacy Act to find out who in the government leaked his name and details of the investigation to the news media.

"For the past 14 months, [Justice Department officials] have been feeding Dr. Hatfill's name to the press," Grannis said.

Walton said that after reviewing the government's secret affidavit, as well as more information Grannis promised to provide on Hatfill's behalf, he will either issue a written ruling on the government's request to freeze the lawsuit or hold an additional hearing Feb. 6.