FBI agents went door to door, asking residents and workers at businesses about suspicious activity. Investigators removed some mailboxes. Two local postal facilities were closed, and nearly 1,000 employees were advised to take antibiotics.
Investigators were drawn to the carrier's route after it was announced Thursday that she had developed an anthrax skin infection. Yesterday, another postal employee, a mail sorter at a regional sorting facility in Hamilton Township, was reported to have developed a similar infection, as did a newsroom staffer at the New York Post's offices in Manhattan.
The victims were on antibiotics and are recovering.
In Washington, authorities said close examination of the anthrax bacteria mailed to offices in Florida, New York and Washington found that the samples were "indistinguishable," suggesting that the attacks were related.
"It does appear that it may have been from the same - the same batch," Homeland Security Director Tom Ridge told reporters at a White House briefing. "But it may have been distributed to different individuals to infect and to send into different communities."
Ridge said the FBI had been able to identify the New Jersey mailbox where anthrax-tainted letters had been sent. But later, FBI special agent Linda Vizi said she knew nothing about it.
Postal officials said the infected carrier's mail route serves about 570 households and businesses, including a Department of Transportation office, a country club and a school for the deaf.
She worked out of the small West Trenton post office in Ewing Township, one of 46 central New Jersey stations that feed mail to the regional distribution facility in Hamilton, where the anthrax-contaminated letters mailed to NBC and to the U.S. Senate were postmarked "Trenton" on Sept. 18 and Oct. 9.
Letter carrier Jim Bittenbender said his colleague did not pick up mail from public boxes, suggesting that any outgoing mail she received would likely have come from addresses on her route, or from someone who handed it to her personally. "That would obviously be among the many avenues we would pursue," said Sandra Carroll, an FBI spokeswoman in Newark.
A 35-year-old man who works at a machine that sorts oversized mail at the Hamilton plant became yesterday the second postal worker in the Trenton area reported to have an anthrax infection. The Levittown, Pa., resident was hospitalized and taking antibiotics to treat an anthrax lesion on his neck.
"It isn't life-threatening in any way," said Richard McGarvey, a spokesman for the Pennsylvania Department of Health. Authorities suspect that a third postal employee is also infected.
State and federal health officials urged all of the nearly 1,000 people who work at the Hamilton facility and the West Trenton post office to take antibiotics until epidemiologists can determine the likelihood that they were exposed to the bacteria.
Both buildings were closed while investigators and health officials examined them for clues and traces of anthrax. Mail processing was shifted to other centers.
Farther north in New Jersey, Carroll said the FBI will run anthrax tests on items removed last month from the apartment of two Jersey City men detained by federal authorities after the Sept. 11 attacks.
The FBI was alerted after Wall Street Journal reporters visited the unlocked apartment of Mohammed Jaweed Azmath and Ayub Ali Khan and found a 1995 article on sarin nerve gas and a magazine article on the National Center for Infectious Diseases.
Azmath and Khan have been detained since they were picked up in Texas on an Amtrak train the day after the Sept. 11 attacks. They were alleged to be carrying about $5,000 and box-cutting knives similar to those used by the hijackers.
The nation's eighth confirmed anthrax case turned up yesterday at the New York Post offices in Manhattan. Company officials said Johanna Huden, 30, an assistant to editorial page editor Bob McManus, was recovering from an anthrax skin infection and is back at work.