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FBI asks microbiologists for help on anthrax

WASHINGTON (CNN) -- Saying "it is very likely that one or more of you know this individual," the FBI has asked the nation's 30,000 microbiologists for help in identifying who sent the deadly anthrax-laced letters last year.

"A review of the information to date in this matter leads investigators to believe that a single person is most likely responsible for these mailings. This person is experienced working in a laboratory," the FBI said in a letter to the members of the American Society for Microbiology.

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Van Harp, director of the FBI's Washington field office and the man in charge of the bureau's anthrax investigation, wrote the letter. It was sent to the biologists in mid-January. CNN obtained the letter Monday.

"I would like to appeal to the talented men and women of the American Society for Microbiology to assist the FBI in identifying the person who mailed these letters. It is very likely that one or more of you know this individual," Harp wrote.

Harp outlined some of the believed characteristics of the person responsible for the anthrax mailings:

-- One person who has a clear, rational thought process and appears to be organized in the production and mailing of these letters.

-- The person has "technical knowledge and/or expertise to produce a highly refined and deadly product," according to the letter.

-- Based on the selection of the Ames strain of anthrax, "one would expect that this individual has or had legitimate access to select biological agents at some time," the letter said.

-- "The perpetrator might be described as 'stand-offish' and likely prefers to work in isolation as opposed to a group/team setting," the letter said.

-- "It is possible this person used off-hours in a laboratory or may have even established an improvised or concealed facility comprised of sufficient equipment to produce the anthrax," the letter went on to say.

"It is important to ensure that all relevant information, no matter how insignificant it may seem, is brought to the attention of investigators in this case," Harp wrote.

The letter reminded the biologists there is a $2.5 million reward for information leading the conviction of anyone responsible for the anthrax mailings.

The letter builds on a profile the FBI released in November, which described the person behind the attacks as a loner, who is non-confrontational and familiar with the Trenton, New Jersey, area, where the letters were mailed.

The FBI said the suspect was probably not connected to the September 11 attacks, but was an opportunist who used the attacks as cover to hide his plan. The letter urged biologists who might have pertinent information to call the FBI at 1-800-CRIME TV or to e-mail them at Amerithrax@fbi.gov.

Five people, including two postal workers, died from inhalation anthrax as a result of the letters. Numerous other individuals were infected with cutaneous, or skin, anthrax, a more treatable form of the disease.