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By Dan Eggen and Susan Schmidt
Washington Post Staff Writers
Saturday, November 17, 2001; Page A01

The FBI discovered a fourth letter yesterday that appears to contain anthrax spores, this one addressed to Sen. Patrick J. Leahy (D-Vt.) but bearing the same Trenton, N.J., postmark and handwriting as others found to contain the deadly microbes.

The letter, discovered yesterday afternoon during a search through barrels of quarantined mail in Northern Virginia, was postmarked Oct. 9 and "appears in every respect to be similar to the other anthrax-laced letters" found in Washington and New York, the FBI said. The letter was sent to a U.S. Army lab for more testing.

A previously discovered letter with the same postmark was sent to Sen. Thomas A. Daschle (D-S.D.), and two others postmarked Sept. 18 in Trenton were mailed to NBC News anchor Tom Brokaw and the New York Post.

Leahy, who chairs the Senate Judiciary Committee, was told of the discovery about 6 p.m., when FBI Director Robert S. Mueller III called him at his Virginia home.

"This is a law enforcement matter, and I will leave it to the proper authorities to report what they know and the procedures they are taking," Leahy said in a statement. "I am confident they are taking the appropriate steps and that eventually they will find this person."

The apparent discovery of a second letter containing anthrax bacteria in the Capitol Hill mail stream represents a fresh opportunity for federal investigators as they hunt for the culprit in the bioterror attacks. Investigators have been stymied by a lack of forensic evidence – no fingerprints, hair or fibers were obtained from the previous letters – and have seen other leads dwindle.

Dan Mihalko, a spokesman for the U.S. Postal Inspection Service, said each new letter offers the possibility of additional forensic evidence. "That's what we hope for," he said. "An additional piece of mail . . . could be useful in the overall investigation."

The letter is also new evidence that the Daschle letter alone may not have led to the deaths of two Washington postal workers employed at the Brentwood postal distribution facility and the illnesses of five others in this area. Some authorities had speculated that at least one more letter containing anthrax spores must be in the postal system.

Four people have died and at least 13 others have been infected with anthrax in New York, Washington and Florida since the bioterror attacks began. In addition to the postal workers, the fatalities included Bob Stevens, a photo editor at a Florida tabloid, and Kathy Nguyen, a hospital worker from the Bronx in New York.

Authorities believe Stevens came in contact with anthrax microbes sent in a letter to his workplace. Nguyen's death is unexplained.

The FBI said the new letter was addressed to "Senator Patrick J. Leahy of Vermont," but it was not clear whether it was meant to be delivered to his suite in the Russell Senate Office Building or to the Senate Judiciary Committee's offices in the Dirksen Building. It was also unclear where in the Capitol mail system authorities stopped the letter.

The Senate mailroom is in Dirksen, which gets mail from a postal facility for congressional mail on P Street SE after it is processed in the Brentwood facility.

All three Senate office buildings were closed after the discovery of the anthrax-laced letter to Daschle on Oct. 15.

FBI behaviorists have theorized that the attacks are the work of a lone, angry male whose first language may not be English and who is probably not associated with the al Qaeda terrorist network accused in the Sept. 11 attacks in New York and Washington.

The Daschle letter was sent in an envelope addressed to the senator's office in the Hart Building with a return address of "4th Grade, Greendale School, Franklin Park, NJ." There is no school by that name in Franklin Park.

The envelopes discovered so far featured two versions of a similar hand-scrawled letter, including the slogans "Death to America" and "Allah is Great." Investigators believe the phrases were likely meant to wrongly cast suspicion on Islamic radicals.

The Leahy letter was discovered in one of about 280 barrels of unopened mail that had been sent to Capitol Hill but quarantined since an aide opened the letter to Daschle in the senator's Hart Building suite. Hazardous materials teams from the FBI are nearly finished sorting through the mail in the 55-gallon drums at a sealed General Service Administration warehouse near Springfield Mall, an official said.

Mihalko said there was powder on the unopened letter and "dust falling out of it." Field tests on the barrel containing the letter turned up positive for anthrax, and it was sent to the U.S. Army lab at Fort Detrick, Md., for more analysis, Mihalko said. A lab spokesman said additional tests will make certain whether the letter contains anthrax bacteria.

Investigators in Springfield have conducted field tests on each of the 280 barrels. The teams, dressed in biohazard suits, are sorting through the mail, beginning with "cool" barrels that registered low spore readings, in order to avoid spreading anthrax contamination from "hot" barrels.

Mihalko could not say last night how many barrels had produced high spore readings. Other officials declined to comment.

The mail being examined was taken from an off-site postal facility near the Capitol, as well as mailrooms in the Ford House Annex and Dirksen. Some office mail was also gathered up and quarantined after the discovery of the Daschle letter, officials said.

Rep. James P. Moran Jr. (D-Va.), whose district includes the FBI's mail screening operation, said the Leahy letter could support the theory that the source is "a domestic, right-wing oriented group."

"Why would they choose the new Senate majority leader and the Senate Judiciary Committee chairman?" Moran said.

Gary Hoitsma, press secretary for Sen. James M. Inhofe (R-Okla.), whose office is at the other end of the floor from Leahy's, said people in Russell thought they were safely removed from danger but now can't be sure.

"Here in Russell, we have a certain level of confidence that it [the anthrax danger] never reached over here," he said. "Now it makes you think twice."

At a news conference last night, Lt. Dan Nichols of the U.S. Capitol Police said the Dirksen and Russell buildings would be closed today for testing of their mailrooms.

Nichols said it was possible that the Leahy letter was in one of those buildings before undelivered mail to lawmakers was gathered and removed.

"We don't know how far the letter went into the mail system," Nichols said. "We feel it is a reasonable and prudent precaution to take. We just want to give peace of mind to the people here."

Greg Martin, an infectious diseases specialist with the Navy, said he doesn't believe there will be further cases of anthrax exposure among Capitol Hill visitors and staff.

"We feel confident that there will be no incidence of disease" from the letter, Martin said, noting the extensive nasal swabs done on Capitol Hill. Capitol physicians are not recommending that more employees be put on antibiotics, Martin said.

The discovery of the Leahy letter does little to explain how three sorting machines in a State Department mail processing facility in Sterling tested positive for anthrax spores.

Investigators believe a letter containing the deadly bacteria must have passed through that building before it was sealed Oct. 24, but it is unlikely that a letter to a U.S. senator would travel that route, officials said.

The discovery also provides no immediate answers to Nguyen's death. She died of inhalation anthrax, but investigators have no evidence that she handled any tainted letters and have found no spores in her apartment, work areas or belongings.

In comments to reporters yesterday before the Leahy letter was discovered, Mueller said the FBI is still working to retrace Nguyen's steps. "The investigators are trying to dissect her life to determine at what point in her day-to-day activities she could have been exposed to anthrax," Mueller said.

Mueller and other FBI officials have conceded in recent weeks that the FBI has been hobbled in its investigation by an unfamiliarity with anthrax bacteria. A senior official told senators earlier this month that the FBI had no idea how many labs handle the bacteria within the United States.

Mueller said yesterday that investigators had made progress in determining the number of labs that could be a source of the bacteria. The same type was discovered in all the previous letters. "I think we've got a good handle on that at this point," he said.

Staff writers Andrew DeMillo, Helen Dewar, Spencer S. Hsu, George Lardner Jr. and Martin Weil contributed to this report.