Washington A letter to Sen. Patrick Leahy contained suspected anthrax and handwriting that appear identical to an earlier letter to Senate Majority Leader Tom Daschle, the FBI disclosed Thursday.
With the letter and the powder undergoing laboratory analysis, "We hope to learn ... who did this and how they did it," said FBI official Van Harp.
The suspected anthrax in the Leahy letter "appears to be consistent with that found in the letter sent to Senator Daschle," Harp said.
The Leahy and Daschle letters state in part, "09-11-01 You can not stop us. We have this anthrax" and conclude, "Allah is great."
It will take weeks to complete all testing, because "there is a finite amount of material in that letter" to Leahy, necessitating "a very cautious analytical approach," Harp, assistant director in charge of the FBI's Washington field office, said in a statement.
Also, a batch of mail being processed at a mail-handling facility set up in a courtyard of the Federal Reserve's headquarters has tested positive for exposure to anthrax, officials said late Thursday.
It had not been determined whether any of the letters there actually contained anthrax spores or whether some of the mail had been contaminated by other letters. Fed spokeswoman Michelle Smith stressed that none of the mail had been inside the Fed's headquarters building.
The FBI posted photographs on its Web site that detailed Wednesday's opening of the Leahy letter at the Army's biodefense laboratory in Fort Detrick, Md.
The first step in dealing with the Leahy letter was to cut a small opening in the envelope and use a machine to suck out the suspected anthrax.
The photographs show a technician's gloved hands inside a laboratory device known as a "glove box," as the technician uses a pair of scissors to clip open one end of the Leahy envelope, then pulls out the letter with tweezers.
Glove boxes typically are set up as negative pressure chambers to ensure that in case of an accidental leak, the material would stay inside rather than escape outward.
Investigators now have four letters in the anthrax probe. Letters to NBC News anchor Tom Brokaw and the New York Post also are identical.
The opening of the Leahy letter was delayed almost three weeks as technicians tried to determine the best way to protect evidence retrieved from it.
In October, some of the anthrax from the letter to Daschle "literally jumped off the slide" and was lost to investigators as lab technicians tried to examine the deadly powder.
The suspected anthrax powder from the Leahy letter will be sent to various labs for analysis.
The letter itself must be decontaminated and irradiated before it can be tested for fingerprints, DNA and fibers.
The Leahy envelope was found by government investigators Nov. 16 among mail quarantined after the Oct. 15 discovery of anthrax in the Daschle letter.
Five people have died of anthrax exposure, and 13 others who became ill have recovered.
The inspector general of the U.S. Postal Service has opened an inquiry into the government's response to the discovery of anthrax spores at a handful of mail facilities.
The four letters to Leahy, Daschle, Brokaw and the New York Post were postmarked Trenton, N.J.