Route of infected N.J. letter carrier searched

TRENTON, New Jersey (CNN) -- A West Trenton post office and the New Jersey capital's main mail processing and distribution center were closed Friday as investigators scoured the buildings for clues to the origin of a strain of anthrax they believe is responsible for several recent releases of the bacteria.

Investigators were also tracing the steps of a West Trenton mail carrier who tested positive for cutaneous (skin) anthrax infection and may have handled anthrax-laced letters postmarked in Trenton.

The letters were addressed to Senate Majority Leader Tom Daschle and NBC Nightly News anchor Tom Brokaw. One NBC employee was been diagnosed with cutaneous anthrax, and 31 people at Daschle's Washington office tested positive for exposure to the bacteria after the letters were opened.

Health officials also said an employee at the Trenton Processing and Distribution Center in Hamilton Township, New Jersey, was a "possible" case of anthrax.

But the mail carrier's route -- about 250 homes and businesses -- could offer investigators clues leading toward possible suspects. The mail carrier picked up stamped letters and delivered mail to the locations on her route, and did not empty any drop boxes.

Six people so far have been diagnosed with the disease -- two in Florida, three in New York and the New Jersey letter carrier -- and 35 people have tested positive for exposure to the bacteria that causes it. One of those infected, a tabloid photo editor in Boca Raton, Florida, died after contracting inhalation anthrax, the most serious form of the disease. A co-worker of that man is the only other confirmed case of inhalation anthrax.

Same-source bacteria possible

All but four of the 35 exposure cases stem from the letter received at Daschle's Washington office.

Investigators said the handwriting was similar on the envelopes of both the Brokaw and Daschle letters, and that preliminary tests indicated the bacteria inside may have been from the same source.

No letters have been found in the Florida case, but authorities believe the anthrax reached the American Media Inc. building through the mail.

Late Thursday, health officials in Palm Beach County, Florida, announced that anthrax spores had been found in preliminary tests in two postal facilities -- one in Boca Raton and one in Lake Worth. Those facilities will not be shut down, they said, but crews decontaminated them overnight.

Looking for evidence that might definitively link the Florida cases with New York and Washington, hazardous materials teams again donned protective suits Friday to scour the American Media building.

Officials announced Thursday a $1 million reward for information leading to the arrest and conviction of those responsible for distributing the potentially deadly bacteria through the mail.

Officials confirmed the latest cases of anthrax, the New Jersey woman and a CBS News employee in New York, on Thursday.

Robert Stevens, the tabloid photo editor, died on Oct. 5 of inhalation anthrax. Ernesto Blanco, an employee in the AMI mailroom, tested positive for inhalation anthrax but is expected to recover.

The three cases of cutaneous anthrax confirmed in New York include a 7-month-old son of an ABC News producer, an employee of NBC News and an employee of CBS News. All are expected to recover.

-- CNN Correspondents Susan Candiotti and Brian Palmer contributed to this report