As a result the investigation has been handled by postal investigators, with the help of the Capitol Police.

But federal law enforcement officials, who recently disclosed the discrepancy in the size of the anthrax particles, called the postal investigators' theory possible but unlikely.

Subpoena power would let postal investigators find out how much of any contributed money is actually spent for the asserted purpose.

He noted only that a team of postal investigators from across the country would begin sorting out the mess sometime this week.

The audit prompted the criminal investigation by postal investigators and the United States Capitol Police.

Last year, postal investigators made more than 500 arrests.

He said he told Mr. Stephens that postal investigators would be better able than the Capitol police to conduct the inquiry.

The letter, summarizing a meeting held a week earlier with postal investigators, said that "the conduct and direction of the inquiry will be under the control of the Postal Inspection Service."

But now postal investigators are not so sure.

F.B.I. and postal investigators concentrated today on the Trenton area, where the letters to NBC and to Mr. Daschle were postmarked on identical prepaid envelopes.