Boca Raton, Fla. Federal officials said they have launched a criminal investigation into the source of anthrax contamination at a supermarket tabloid after learning a third employee was exposed.
The announcement marked the most declarative statement yet about an anthrax investigation that comes as the nation is on a heightened terrorism alert. Officials have hinted that it could turn into a criminal investigation but never have been so assertive about the direction of the probe.
The bacteria has already killed one man and put a co-worker in the hospital, prompting widespread concern about bioterrorism. But the FBI said there was no evidence linking the anthrax to a terrorist group.
A nasal swab taken from a 35-year-old woman, whose name wasn't released, tested positive for the presence of anthrax, U.S. Attorney Guy Lewis said Wednesday. She was being treated with antibiotics at a hospital and her condition was not immediately known.
Investigators wearing white moon suits and gas masks were working through the night into Thursday collecting evidence in the newspaper offices of American Media, Inc., which publishes six tabloids.
"The FBI is going through the building on a methodical basis. Floor by floor, cubicle by cubicle, area by area," said FBI special agent Hector Pesquera.
The woman was one of more than 1,000 people tested by health officials, who took nasal swabs and blood tests from those who recently had been inside the company headquarters.
The search so far has turned up no further sign of anthrax since traces were discovered on the computer keyboard of Robert Stevens, 63, who died Friday of inhaled anthrax, an especially rare form of the disease. Co-worker Ernesto Blanco, 73, has been in a Miami hospital since Monday after he was found to have anthrax spores in his nose.
"This is so devastating to me and my company," AMI chief executive David Pecker said on CNN's "Larry King Live." Pecker said he thought his company was being targeted.
Pesquera said the anthrax contamination was limited to the building and added "this is not a time for premature conclusions and inaccurate reporting."
Company employees began taking blood tests on Wednesday at the company's offices. County and state health department officials ordered the building closed for 30 days.
Health officials have emphasized that there is no public health threat. Anthrax tests at Stevens' home were negative, said Dr. Jean Malecki, director of the Palm Beach Health Department.
Preliminary testing at federal labs on the anthrax that killed Stevens has found a possible match to a strain connected to an Iowa lab, a law enforcement official said Wednesday. The official, speaking on condition of anonymity, said further testing to make a definitive match could take several days.
The anthrax bacterium normally has an incubation period of up to seven days, but could take up to 60 days to develop.
"This can happen to anybody." Pecker said. "This can happen to Time Warner. This can happen to the New York Times."