BOCA RATON -- Federal investigators and scientists searched for clues inside the anthrax-infested former home of The National Enquirer for a fifth day Tuesday after collecting hundreds of samples through the holiday weekend.
Investigators said their work has been "successful" but declined to say whether they have found whatever brought the anthrax inside the building, a key piece of evidence in the 11-month-old criminal investigation.
The investigation will continue until at least Sept. 11, the deadline FBI agents set in their search warrant for the building, owned by tabloid publisher American Media Inc. AMI spokesman Gerald McKelvey said the warrant could be extended.
"There's a lot of space to go over," McKelvey said of the three-story, 67,000 square-foot building.
Police Cmdr. Maria Maughan said investigators tried new sampling techniques Tuesday. She declined to elaborate on the techniques or the samples being taken from the building but said hundreds of samples have been collected from all three floors.
Although federal investigators searched the AMI building in October, after photo editor Robert Stevens was fatally infected, they say they have developed new techniques to search for large amounts of anthrax and hope to follow a trail of spores to the source.
In addition to finding the source of the anthrax, the teams of FBI agents and scientists hope to compare large samples of anthrax spores found inside the AMI building to those found in letters sent to the congressional offices of Sens. Patrick Leahy of Vermont and Tom Daschle of South Dakota.
The comparisons could help revive the slow-moving investigation into the attacks, which killed Stevens and four others. Another American Media worker, mailroom employee Ernesto Blanco, became ill and was hospitalized more than three weeks.
Federal officials quarantined the building Oct. 7, and AMI officials soon moved their headquarters to rented offices less than a mile away. The company publishes six supermarket tabloids, including the Enquirer, Globe and Weekly World News.