The FBI publicly declares Dr. Steven J. Hatfill no more or less important than 30 "people of interest" in the investigation into last fall's anthrax attacks, but law enforcement officials concede he is being treated differently.

Hatfill's photo is the only one being shown to residents of the Princeton, N.J., neighborhood where a mailbox tested positive for anthrax last week.

And a U.S. official close to the case, speaking on condition of anonymity, said Hatfill's apartment was the only home searched under a warrant in connection to the case.

Several FBI and Justice Department officials declined to comment Wednesday on whether the circulation of Hatfill's picture signifies an advancement in the investigation into who killed five people and sickened 13 others by sending anthrax through the mail.

Hatfill's spokesman, Pat Clawson, said it's time for the FBI to either reveal why the government is interested in Hatfill or clear him.

"The only thing the FBI has said is that he has a very colorful background, yet they are destroying this man's reputation," Clawson said. "Normally when you're doing a photo canvassing you have photos of more than one person, because you want to eliminate false identifications. The fact that the FBI is using only one photo makes the entire process suspect."

Clawson also noted that the FBI had confiscated all of Hatfill's travel documents and records.

This week, Hatfill's attorneys filed a complaint about the FBI investigation to oversight offices at the Justice Department and the FBI. The complaint alleges officials leaked information about Hatfill to the press, including that he was a "person of interest" in the case, Clawson said.

Hatfill, 48, previously worked at the Army Medical Research Institute at Fort Detrick, Md., once home to the U.S. biological warfare program and a repository for the Ames strain of anthrax used in the attacks.

At a news conference Sunday, Hatfill proclaimed his innocence and allegiance to America, condemned the FBI's investigation of him and emphasized that his background is in the study of viral diseases such as Ebola, not bacterial diseases such as anthrax. His lawyer said Wednesday that Hatfill has never been to Princeton.

A senior U.S. law enforcement official confirmed Wednesday that the FBI began showing Hatfill's photo around Princeton on Monday. The agents are trying to determine whether anyone saw Hatfill last September or October near a mailbox where authorities believe the anthrax letters were mailed, the official said, speaking on condition of anonymity.

One senior law enforcement official said the FBI was avoiding discussion of Hatfill to prevent a "Richard Jewell" situation.

The FBI targeted Jewell as a suspect in the bombing at the 1996 Summer Games that killed one person and injured more than 100. Jewell insisted he was innocent and complained the FBI's investigation had ruined his career and personal life. He never was charged and was publicly cleared three months later with a government apology.

Legal experts say even without calling Hatfill a suspect, the FBI is making Hatfill look like one.

"I think law enforcement does have the right to go around and show the pictures of suspects to people," said Lawrence Goldman, president of the National Association of Criminal Defense Lawyers. "But when there is little evidence of wrongdoing, the FBI has to be very careful. There is a general lack of sensitivity in law enforcement as to how reputations are destroyed."

Buck Revell, a former FBI counterterrorism chief, said circulating a picture is not unusual and probably does not signify a development in the case.

"It is a routine part of an investigation," Revell said. "It doesn't mean they are ready to charge him or that he is the only potential suspect, but it does show a continuing interest on the part of the FBI."

Revell also said the intent of FBI photo canvassing is to establish the possibility that a person was in an area, not necessarily to accumulate evidence for a trial. When trying to amass evidence for prosecution, investigators generally do a "photo lineup," showing witnesses a picture of a suspect among several photos of people with the same general features.

Federal authorities have sampled 600 mailboxes in New Jersey since last fall, including the mailbox in Princeton, which is believed to be the first to test positive for anthrax spores. Thirty-nine tests are outstanding.