The FBI denied yesterday that anthrax investigators have smeared a former Army bioterrorism expert with leaks to the news media but said it would look into some allegations of misconduct made by Dr. Steven J. Hatfill.

FBI spokesman Chris Murray said agents did not reveal Hatfill's identity to reporters or tip them off in advance to searches of his Frederick apartment June 25 and Aug. 1.

"We're not aware of any FBI employee who has named a 'suspect' in the anthrax deaths investigation," Murray said. Also, he said, "the FBI does not alert the news media to the service of search warrants."

He added, however, "credible allegations concerning the mishandling of evidence will be investigated thoroughly." The FBI spokesman did not elaborate, but Hatfill's attorney, Victor M. Glasberg, alleged Sunday that the text of a bioterrorism novel written by Hatfill had been leaked to a TV network.

But a day after Hatfill's emotional statement at a news conference that public attention has made his life a "wasteland," the bureau declined to clear him. There was no sign that he has been ruled out as a potential suspect in the mailing of anthrax letters that killed five people and sickened at least 17 others last fall.

One new piece of evidence surfaced yesterday in the 10-month-old investigation. Officials in New Jersey, where the deadly letters were mailed, confirmed that anthrax spores were found last week on swabs taken from a mailbox in the business district of Princeton. The only mailbox to test positive of 561 tested, it may provide clues to the path of the anthrax mailer, they said.

No spores were found in Hatfill's apartment, law enforcement officials say, and no physical evidence links him to the mailings.

In light of that, some outside experts supported yesterday Hatfill's assertion that he has been unfairly targeted by investigators, who are under intense pressure to solve the case by the Sept. 18 anniversary of the first anthrax mailing.

"He's being railroaded," said Richard O. Spertzel, who headed the United Nation's biological weapons inspections in Iraq from 1995 to 1998. "I'm afraid they're creating another Richard Jewell," he added, referring to the security guard wrongly accused of planting a bomb at the Atlanta Olympics in 1996.

Spertzel, of Frederick, who said he has met Hatfill but does not know him well, said swabbing Hatfill's apartment for anthrax spores many months after the anthrax powder was prepared was a waste of time.

"There were plenty of two-legged guinea pigs in that apartment complex. If the anthrax had been made there, his neighbors would be dead," said Spertzel. He believes the anthrax was made in a sophisticated lab.

Hatfill, who trained as a physician but has forged a career since 1997 as a bioterrorism consultant, is among a number of scientists brought to investigators' attention because of their knowledge of biological agents and access to supplies of the Ames strain of anthrax used in the attacks.

But the two very public searches of Hatfill's apartment, as well as his colorful history and episodes of embellishing his resume, have focused far more attention on him than on any of the other potential suspects.

At times, Hatfill's friends say, the rumor mill among scientists and reporters following the anthrax investigation has distorted innocent acts by Hatfill, making them seem ominous. As an example, they point to a widely repeated report about a country house that Hatfill visited last fall.

In mid-June, two weeks before the first search of his apartment, biologist Barbara Hatch Rosenberg sent biodefense experts and reporters an account of a "likely suspect" who "had access to a conveniently located but remote location where activities could have been conducted without risk of observation." She wrote of evidence "that the suspect knew in October that the remote site was contaminated with anthrax."

On July 2, New York Times columnist Nicholas D. Kristof, calling the Hatfill-like suspect "Mr. Z.," accused the FBI of "lethargy" in pursuing the suspect and elaborated on the "remote site" theory.

"Have you searched the isolated residence that he had access to last fall?" Kristof asked the FBI in a series of rhetorical questions. "The FBI has known about this building, and knows that Mr. Z gave Cipro to people who visited it. This property and many others are legally registered in the name of a friend of Mr. Z, but may be safe houses operated by American intelligence."

Pat Clawson, a broadcasting executive and former CNN reporter who has known Hatfill socially for six years, said he and Hatfill are part of a group of friends who visited a house in the Virginia mountains near Shenandoah National Park in October for a weekend of skeet-shooting and socializing.

The visit, in the middle of that month, came at the peak of anthrax hysteria, Clawson said. He told Hatfill that a few weeks earlier he had opened a vitriolic letter addressed to Oliver North, whose radio program is produced by Clawson's employer, Radio America. White powder had spilled from the envelope, which Clawson discarded.