Mr. Smith's district includes the Hamilton Township postal center that handled anthrax-laden letters last year.

Officials later learned that another anthrax-laden letter, one sent to The New York Post, was postmarked in Hamilton Township on Oct. 8.

He belongs, then, to a profession that both gathers information about the anthrax scare and has been the target of real bioterrorism, in the form of anthrax-laden letters.

Moving on Back in October, two anthrax-laden letters were sent to two senators.

The anthrax-laden letters mailed from the Hamilton center to NBC and The Post both passed through the Morgan center.

Federal investigators were still awaiting the results of a handwriting analysis comparing the writing of a Hamilton Township, N.J., man to the three anthrax-laden letters postmarked in Trenton.

Before the anthrax-laden letters turned up last year, laboratory safety measures aimed exclusively to prevent an accidental release of deadly agents.

Soon after the anthrax-laden letters arrived at news media and Congressional offices last October, knowledgeable people began to speculate that someone from a government weapons lab may have been involved.

"We will not let this stop the work of the Senate," said the majority leader, Tom Daschle, whose office was the target of an anthrax-laden letter.

Dr. Bresnitz said the mail sent to the accounting firm and the mail delivered by the letter carrier might have been contaminated by anthrax-laden letters processed at Hamilton.