The investigation into last fall's deadly anthrax attack has thrown an intense focus on Army scientists at Fort Detrick, putting the very people whose job has been to protect the nation from bioterror under suspicion.

Former and current scientists at the military lab have been called for interviews by federal authorities, and some have been subjected to polygraph tests and home searches.

Dr. Steven J. Hatfill, a former Fort Detrick scientist whose home was searched this past week, has complained the scrutiny cost him his job at a private company.

"I think it does put them in an awkward situation," said Norman Covert, former spokesman and former command historian for Fort Detrick, who keeps in close touch with many of his old colleagues.

"In the past, people wouldn't question what they did or why they did it," he said. "Now we're saying, 'Maybe you aren't the good guys.' But they really are the good guys."

The investigations at Fort Detrick's Army Medical Research Institute of Infectious Diseases, the military's premier bioterrorism complex, have not produced any arrests in the search for the culprit or culprits behind anthrax-laced letters that killed five people last year.

"It's just like anything else — when you put out a dragnet, you're going to get a lot of innocent people," said David Huxsoll, who commanded the Army institute in the 1980s.

Hatfill has been cooperating with the FBI and has been told repeatedly that he is not a suspect in the anthrax mailings, his lawyer said Friday.

"He feels like he has a good name, and it's being damaged by the situation," said lawyer Thomas C. Carter of Alexandria, Va. "It's distressing to have his name mentioned in same paragraph as all these terrible crimes."

The institute is the main custodian of the particularly virulent type of anthrax known as the Ames strain that was used in the mailings last year to politicians and news organizations that also contaminated several postal facilities.

Up to 200 polygraph tests have been given to current and former employees of the institute and of Dugway Proving Ground in Utah, where scientists have developed a powdered form of anthrax for testing biological defense systems, law enforcement officials said.

Meanwhile, the 125 Ph.D.-level scientists at the institute continue to research bioterror. Part of their work is analyzing samples taken from Post Offices and legislative offices last fall, said base spokesman Chuck Dasey.

"They're trying to get on with their work, but the FBI is kind of underfoot," Covert said. "Big brother is looking over their shoulder all the time, and big brother doesn't even know what ... they're looking for."

News coverage of the FBI's searches of Hatfill's home and a self-storage unit he rented in Florida intensified when reports surfaced that he had commissioned a 1999 report detailing how to send anthrax through the mail. Law enforcement officials say he is one of 20 to 30 scientists who might have had the know-how and opportunity to mail the deadly letters.

Hatfill worked for two years in the institute on a fellowship from the National Research Council, Dasey said. Although he probably had access to anthrax, his primary duties didn't involve working with it, the spokesman said. In September 1999, he left. He was employed by Science Applications International until March. Carter wasn't sure if he is currently working.

Despite the scrutiny of Fort Detrick, former institute scientists and retired Col. David Franz, commander of the institute from 1995 to 1998, said the investigations are necessary — and that most Army scientists won't mind them.

"We ought to all be looked at. Law enforcement would be doing a disservice if it didn't look at everyone," Franz said. "But intent is hard to measure. I don't know anyone with intent, but we all have the capability."