Federal investigators returned last month to the American Media Inc. building for 12 days, armed with new techniques for detecting large quantities of anthrax.
The Palm Beach Post quotes a source as saying that the investigating team found anthrax spores in all the copy machines in the three-story, 68,000 square foot building.
Investigators are considering the theory that the microscopic spores spread from the first-floor mailroom where the tainted letter was first opened and onto reams of copier paper stored there. The spores might then have spread into the air by fans inside the machines loaded with the copier paper.
The building housed more than two dozen copy machines. The FBI's theory helps explain for the first time the presence of anthrax throughout the building.
"Once it falls, it stays," Palm Beach County Health Department spokesman Tim O'Connor said. "It was stuck to the keyboard in Stevens' office. It stuck in the machinery that sorts the mail in post offices."
The FBI's search operation began Aug. 27 and ended Sept. 8. It was the first comprehensive search of the supermarket tabloid's publishing office.
According to court documents, hundreds of letters, 33 mail-cart folders, 12 mailroom shelves, 11 mail-slot vacuum samplings and 11 box tops collected throughout the mail room were seized from the building by investigators. They also took two vacuum samples and six carpet samples.
Photo editor Robert Stevens died from anthrax in October. He was the first of five people to die nationwide in the anthrax attacks. Ernesto Blanco, who worked in the AMI mail room, was hospitalized with anthrax but survived.
The building was under continuous security since it was placed under federal quarantine Oct. 7.
The company, which publishes six supermarket tabloids, including The National Enquirer and Globe, moved its headquarters to rented offices nearby.