Leahy letter sole suspicious one in quarantined mail

WASHINGTON (CNN) -- The only suspicious letter among 280 barrels of quarantined congressional mail was the one addressed to Sen. Patrick Leahy, the FBI and postal inspectors said Monday. That letter is being analyzed at an Army lab after field tests indicated anthrax contamination, they said.

Hazardous material experts have finished sorting through the congressional mail, according to an FBI spokesman, who said authorities are now awaiting word from congressional leaders on what to do with the mail, which has not gone through any decontamination process.

The congressional mail -- an estimated 635 bags -- was seized last month after an anthrax-tainted letter was opened in the office of Senate Majority Leader Tom Daschle.

Investigators found the Leahy letter Friday and say it was similar -- particularly in the handwriting -- to letters sent to Daschle and two news outlets. Preliminary tests on the envelope for the Leahy letter tested positive for anthrax, according to the FBI, but the barrel holding that letter was the only "hot spot" among the congressional mail. And no other letters in that barrel or the others -- held at a facility in Virginia -- have caught the attention of investigators.

The Leahy letter is being tested at Fort Detrick, Maryland.

Two Senate office buildings that had been closed over the weekend for anthrax testing reopened at 8 a.m. Monday.

The Russell and Dirksen buildings had been closed for environmental sampling after the Leahy letter was discovered.

The Hart building, where the Daschle letter was sent last month, remains closed.