Two of the three office buildings at the U.S. Senate here reopened Monday after being swept for anthrax contamination. This, just three days after the discovery of the latest letter suspected of containing the bacteria.

Only the Hart Senate office building remained closed as Congress began a Thanksgiving week break. The Hart building is where an anthrax-tainted letter was opened Oct. 15 in the office of Senate Majority Leader Tom Daschle, D-S.D.

The Dirksen and Russell Senate buildings were closed Saturday after a letter mailed to Sen. Patrick Leahy, D-Vt., was discovered in one of 280 barrels of congressional mail quarantined after the contaminated Daschle letter was opened. Leahy's letter resembled Daschle's.

Capitol Police spokesman Lt. Dan Nichols said Sunday the letter to Leahy was being analyzed at the Army's Fort Detrick in Maryland. He said test results were not expected for several days, but Leahy spokesman David Carle said the results might be available Monday.

It was unclear whether the letter to Leahy ever reached his office, said the senator's chief of staff, Luke Albee.

The envelopes addressed to Daschle and Leahy were similar, except for the name and address. They both had block printing with a slight slant to the right; an Oct. 9 postmark from Trenton, N.J.; and the same, nonexistent school listed as the return address.

The FBI said all congressional mail set aside after discovery of the Daschle letter has been inspected, and the Leahy letter was the only suspicious piece.

No Senate or House member or aide has contracted anthrax, and congressional business largely returned to normal before this week's Thanksgiving recess. National Guard troops, however, were deployed over the weekend to help relieve overburdened Capitol Police officers.

Four people have died from anthrax: two Washington postal workers, a hospital employee in New York City and a newspaper photo editor in Florida.