Search is on for anthrax leads at tabloid offices

Investigation may take two weeks; CDC assisting

Agents entered the American Media Inc. building in Boca Raton, Florida, on Friday, in a new search for new clues in last year's anthrax attacks.

BOCA RATON, Florida (CNN) -- Investigators in protective suits Friday returned to the offices of supermarket tabloid publisher American Media Inc., hoping to find new clues in last year's deadly anthrax attacks.

American Media's anthrax-contaminated headquarters has been closed since October, when the bacteria killed photo editor Bob Stevens and sickened another employee, Ernesto Blanco.

No letter that might have spread anthrax inside the American Media building was found after last year's attacks. Finding such a letter, if one exists, is one of the goals of the search that began Friday.

Investigators who entered the building wore personal protective equipment and chemical-resistant suits, gloves, and boots. Samples will be taken to a public health laboratory in Miami for analysis.

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The Justice Department sent a letter Friday to AMI, reassuring the company that federal agents will not be going through business records or computer files and have no intention of compromising the company's journalistic work or sources. In addition to The Sun, AMI publishes the National Enquirer, the Globe and the Weekly World News.

A federal law enforcement source told CNN it remains unclear whether the company was a specific target of the anthrax attack: "It may have been a case of cross-contamination," the source said.

Investigators say they believe such cross-contamination is to blame for two of the anthrax deaths, those of an elderly woman in Connecticut and a hospital employee in New York.

Investigators say the FBI did not intensify its search for a presumed anthrax letter at the AMI building until 10 months after the first anthrax death because, in part, the FBI was concentrating on its massive search in Washington following anthrax letters discovered there. Techniques for locating the bacteria and studying its makeup have also improved since the investigation began.

"The building in Florida was sealed, and we knew the spores there would be confined. They can live for 100 years or more," the source said.

Boca Raton Police Chief Andrew Scott said officials have assured him that the renewed activity by investigators poses no health hazard to the surrounding community. The building has been closed and guarded by Boca Raton police and guards hired by AMI, Scott said.

"We've been very diligent to maintain this building as a pure crime scene with no to little entry inside the building," he said.

The Boca Raton search will take about two weeks, and will be aided by investigators from the Centers for Disease Control and Prevention, FBI spokesman Hector Pesquera said earlier this week.

Stevens worked on the third floor as a photo editor for The Sun, a tabloid published by American Media. He died Oct. 5, three days after he entered the hospital with flu-like symptoms.

In all, 22 people were sickened and five died after a series of anthrax attacks that targeted news agencies in New York and a congressional office building in Washington.

-- CNN Correspondents Mark Potter and Susan Candiotti contributed to this report.