Dr. Steven J. Hatfill's firing from Louisiana State University came after the Justice Department ordered the school not to use him on projects funded by grants from the agency, which has called Hatfill a "person of interest" in the anthrax attacks.

Hatfill's supervisor, Steven Guillot, received an e-mail Aug. 1 directing him to "immediately cease and desist" from using Hatfill on the projects, LSU spokesman Gene Sands said Wednesday.

The next day, Hatfill was placed on administrative leave as director of LSU's National Center for Biomedical Research and Training. The center receives much of its money from the Justice Department.

LSU contends the decision to put Hatfill on administrative leave and later, fire him, was not connected to the e-mail.

Sands said Guillot did not alert senior university officials to the e-mail when he received it. Senior LSU officials did not learn of the e-mail until Tuesday, after they had already decided to fire Hatfill, Sands said.

LSU is investigating why senior university officials were not told about the e-mail.

Reports of the Justice Department e-mail sent many federal officials, even within the department, searching for details about it.

Senior Justice Department officials said the e-mail was sent by Tim Beres, acting head of the agency's Office for Domestic Preparedness. Beres sent the e-mail without the knowledge of top officials connected to the anthrax investigation and he never informed them of it, according to officials.

In a statement, Assistant Attorney General Deborah Daniels defended the e-mail, noting that Justice Department grant money is given only with the understanding that the agency can control who works on projects.

Pat Clawson, Hatfill's spokesman, said Hatfill learned of the Justice Department e-mail on Wednesday. Clawson said it was an attempt to pressure Hatfill into a false confession.

"We're stunned to learn of this," Clawson said. "We're outraged. Blacklisting by the government is offensive and un-American. ... Where was the due process?"

Clawson said Hatfill's attorneys have filed Freedom of Information Act requests with LSU and the Justice Department seeking information about the e-mail.

Five people were killed by anthrax-tainted letters sent through the mail last fall. The FBI has identified Hatfill as "person of interest" in its investigation but says he is no more or less important than about 30 fellow scientists and researchers with the expertise and opportunity to conduct the attacks.

Hatfill has repeatedly denied any involvement in the attacks and says the Justice Department is ruining his life by linking him to the crimes.

The e-mail was sent during a flurry of investigative activity surrounding Hatfill. The FBI searched Hatfill's home on Aug. 1 and, less than two weeks later, circulated Hatfill's photo in a Princeton, N.J., neighborhood where investigators believe the anthrax letters might have been sent.

Former FBI analyst Paul Moore said the agency apparently was trying to pressure Hatfill into revealing information.

"When you do see the FBI doing these kinds of public things, they have come to a dead end in an investigation and they need to apply some pressure somehow," said Moore, an analyst for the Centre for Counterintelligence and Security Studies, a private research firm.

Buck Revell, a former FBI counterterrorism chief, said he had never heard of the FBI asking a university to remove a person from government research because of an investigation.

"It is extraordinary," Revell said. "But with there being the involvement of potential biological weapons of mass destruction, investigators have a right to take such actions."

Several criminal defense attorneys said even if Hatfill never is definitively linked to the attacks, he probably would not win a lawsuit based on his dismissal from LSU.

"The courts have said that there really is no entitlement to a job," said Lawrence Goldman, president of the National Association of Criminal Defense Lawyers. "Especially when dealing with sensitive information or potentially deadly substances. There is no standard of reasonable doubt when determining whether someone was fired wrongfully. Suspicion can be enough."

Hatfill, 48, worked until 1999 for Fort Detrick's Army Medical Research Institute of Infectious Diseases in Maryland. It is the primary custodian of the virulent Ames strain of anthrax found in the anthrax letters.