Anthrax letter found at New York Post

The anthrax was found in a mail-sorting machine inside the Ford House Office Building.

(CNN) -- A letter found by police in the mailroom of the New York Post newspaper has tested positive for anthrax and has the same postmark as anthrax-laced letters sent to Sen. Tom Daschle and NBC News anchor Tom Brokaw, an FBI official said Saturday.

Special Agent Joe Valiquette said the unopened letter was found Friday night in the course of the investigation at the Post, after Johanna Huden, an editorial page assistant, was diagnosed with cutaneous (skin) anthrax. Valiquette said agents felt a granular substance through the envelope.

However, Valiquette said, it is not at all clear that the letter that tested positive for anthrax is the one that infected Huden.

The agent said the letter, which was postmarked September 18 from Trenton, New Jersey -- the same postmark as the letter to Brokaw -- had no return address. He said the block-style handwriting was also similar to the letters sent to Brokaw and to Senate Majority Leader Daschle, D-South Dakota.

Meanwhile, in Washington, investigators found traces of anthrax at two separate offices that handle mail sent to Capitol Hill, officials said Saturday.

Capitol Hill Police spokesman Lt. Dan Nichols said a swab taken Wednesday from a mail bundling machine in the Ford House Office Building mailroom tested positive for the bacteria Saturday morning. Tests on the other machines came back negative.

Anthrax spores also turned up in the Capitol Police's off-site mail delivery center, about 15 blocks from Capitol Hill, where all mail for Congress is received, Nichols said.

The House has been out of session since Wednesday night. Health investigators began sweeping the Capitol complex Wednesday and continued to do so through the weekend -- wiping down surfaces, vacuuming and testing the air for any trace of anthrax, said Roger Gibbs of the Department of Defense.

VIDEO CNN's Deborah Feyerick outlines the growing number of U.S. anthrax cases and the expanding investigation (October 20) Play video (QuickTime, Real or Windows Media)

MORE STORIES Mail machine in House has traces of anthrax    IN-DEPTH  VIDEO/AUDIO   •Anthrax scare spreads   •On the hunt for Anthrax  MORE STORIES   • Investigators look for links   • Tracing the mail route  EXTRA INFORMATION   • Biological and chemical weapons   •Testing for anthrax  RESOURCES   •Advice on suspicious packages   •Message board  Complete coverage  If you receive a suspicious package: Handle with care; don't shake or bump Isolate and look for indicators Don't open, smell or taste Treat it as suspect; call 911 Source: FBI

A spokesman for House Speaker Dennis Hastert said the House would definitely be back in session Tuesday, its next scheduled meeting time.

The discovery comes five days after a letter containing anthrax was opened in Daschle's offices. Anthrax spores were also found in the Senate mailroom in the Dirksen Senate Office Building. Tests of over 4,000 people in and around the Senate this week revealed that 28 people, mostly in Daschle's office, had been exposed to anthrax. There have been no reports of anyone getting infected by the bacteria.

"This is a developing investigation and we don't know if there is another letter, it's something we're looking into," Nichols said. "This is possibly cross-contamination with the letter that was received by Senator Daschle." (Full story)

Eight people -- including one man who died -- have tested positive for anthrax infection since October 1, according to the Centers for Disease Control and Prevention, and 32 others have tested positive for exposure to the bacteria. (Full story)

Latest developments

• The most recent tests for anthrax in Gov. George Pataki's Manhattan offices were negative, New York state health officials said Saturday. A preliminary test of a sample from one area of the offices came back positive Wednesday. More complete tests are being conducted on that sample. Results from 90 additional tests came back negative.

• A laboratory in Brazil reported Saturday that a letter -- which was sent to the New York Times' bureau in Rio de Janeiro -- that tested positive for anthrax in preliminary tests has subsequently tested negative. The Times said the letter, sent from New York City on October 5 and received on October 16, seemed suspicious because it had no return address. It was not opened and was turned in to Brazilian authorities.

• On Thursday, Kenyan health officials said a letter -- sent on September 8 from Atlanta, Georgia, and arriving via Miami at a Nairobi businessman's address on October 9 -- tested positive for anthrax. Several other letters sent to Kenya, including two mailed to the United Nations office there, have tested negative. (Full story)

• Argentina's health minister confirmed Friday that a letter sent to an American family in Buenos Aires tested positive for anthrax. It was sent from Miami, Florida, with a Carnival Cruise Lines' return address, according to the director of the laboratory that tested the letter. The person who handled the letter has tested negative. A spokesman for Carnival said the cruise line has received no notice from Argentine health officials.

• In addition, two New Jersey postal workers -- a Trenton letter carrier and a mail-sorter at the Hamilton Township distribution center -- have tested positive for cutaneous (skin) anthrax. Investigators are looking for a link between these infections and the anthrax letters sent to NBC anchorman Tom Brokaw and Senate Majority Leader Tom Daschle, both of which apparently came from New Jersey. (Full story)

• The West Trenton, New Jersey, post office where the infected letter carrier worked and the region's main mail processing and distribution center were closed Friday as investigators scoured the buildings for clues to the origin of the anthrax.

• Director of Homeland Security Tom Ridge had said federal officials know where some of the anthrax letters were put in the mail. But FBI Special Agent Linda Vizi in Philadelphia, Pennsylvania, said the FBI has not pinpointed a single mailbox or a single source of the anthrax.

• Northwest Airlines banned sugar substitutes and non-dairy creamers from its airplanes to avoid anthrax scares sparked by the white, powdery substances. (Full story)

CNN's Susan Candiotti, Eileen O'Connor and Terry Frieden contributed to this report.