A senior U.S. law enforcement official on Wednesday confirmed that FBI officers are showing Steven J. Hatfill's photograph to business owners in the area.
The agents are trying to determine whether anyone saw the 48-year-old former Army biological weapons researcher near the mailbox last September or October when the anthrax-laced letters were mailed, the official said, speaking on condition of anonymity.
An FBI official would not say what, if anything, authorities had learned from people who saw the photo.
Ross N.A. Woolley, an architect with Woolley & Morris in Princeton, said investigators showed him a picture of Hatfill with a mustache, much like a photograph widely shown in the media.
"I immediately recognized it," Woolley said Wednesday.
In a related development, investigators are looking at an unpublished novel written by Hatfill. The book describes a paralyzing bioterror attack against the White House and Congress in which dozens of people sicken or die, including the fictional president and top congressional leaders. But the novel does not involve anthrax or mailings.
Hatfill, a 48-year-old former Army biological weapons researcher, has denied any role in the anthrax-by-mail attacks and has criticized the FBI and media for engaging in what he described as personally damaging speculation and innuendo. When he spoke at a news conference Sunday, he no longer had a mustache.
The FBI says Hatfill is not considered a suspect, but it also says he is one of about 30 "persons of interest" in the case, and his name is the only one to become public.
Several Princeton merchants told The Associated Press that agents spent two days circulating the picture and asking employees if they recall seeing the man in the area last September and October — the height of the anthrax attacks. They said the agents didn't reveal the man's identity.
"He looked like a regular, average guy," Stefani Squitieri, who works at the Origins store on Nassau Street, said about the photo. Squitieri said she didn't work there last fall and hadn't seen the man.
The picture, Squitieri said, appeared to be an identification photo, such as an image taken from a license.
Bill Evanina, an FBI agent in Newark, said the agents' presence was related to Monday's announcement of the positive anthrax test but would not give details.
"We are conducting a logical investigation and canvassing the area," Evanina said.
It wasn't clear when the anthrax spores were found on the mailbox on Nassau Street, the main thoroughfare through downtown Princeton. Authorities received the test results Thursday, but did not make them public until this week. They have not said when the tests were done.
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.
Mail in Princeton is processed by the regional plant in Hamilton, which handled anthrax-tainted letters sent last year to anchor Tom Brokaw, U.S. Sens. Tom Daschle and Patrick Leahy and the New York Post.
Five people died and 13 others fell ill during the anthrax attacks. No arrests have been made, despite a $2.5 million reward.
Hatfill previously worked at the Army Medical Research Institute at Fort Detrick, Md., once home to the U.S. biological warfare program and repository for the Ames strain of anthrax that was used in the attacks. But he emphasized this week that his background is in the study of viral diseases such as Ebola, not