A second test of the anthrax-laced letter sent to Senate Majority Leader Tom Daschle also indicates the presence a troubling chemical additive, sources tell ABCNEWS.
MORE INVESTIGATIVE NEWS: • Atta Met Iraqi Official in Prague • FBI Under Fire for Missteps • Italians Investigate Man Found in Box
Four well-placed and separate sources told ABCNEWS that initial tests also detected bentonite, though White House said initially the chemical was not found.
The first battery of tests, conducted at Ft. Detrick, Md., and elsewhere, discovered the anthrax spores were treated with bentonite, a substance that keeps the tiny particles floating in the air by preventing them from sticking together. The easier the particles are to inhale, the more deadly they are.
As far as is known, only one country, Iraq, has used bentonite to produce biological weapons, though officials caution that the presence of the chemical does not constitute firm evidence of Iraqi involvement.
White House spokesman Ari Fleischer had denied bentonite was found on the letters, but another senior White House official backed off Fleischer's comments, saying "at this point" there does not appear to be bentonite.
The official said the Ft. Detrick findings represented an "opinionated analysis," that three other labs are conducting tests, and that one of those labs had contradicted the bentonite finding. But, the official added, "tests continue."
Fleischer added that no test or analysis has concluded that bentonite is present in the Daschle anthrax, and "no other finding contradicts or calls into question" that conclusion.
Reading from what he said was a sentence from the report prepared by scientists at Fort Detrick, he told ABCNEWS, "It is interesting to note there is no evidence of aluminum in the sample." Aluminum, Fleischer said, would also be present if bentonite was.
Defense Secretary Donald Rumsfeld said that the anthrax letters were being carefully investigated, but did not confirm or deny the presence of bentonite in the Daschle letter.
While it's possible countries other than Iraq may be using the additive, it is a trademark of Iraqi leader Saddam Hussein's biological weapons program.
"It means to me that Iraq becomes the prime suspect as the source of the anthrax used in these letters," former U.N. weapons inspector Timothy Trevan told ABCNEWS.
In the process of destroying much of Iraq's biological arsenal, U.N. teams first discovered Iraq was using bentonite, which is found in soil around the world, including the United States and Iraq.
"That discovery was proof positive of how they were using bentonite to make small particles," former U.N. weapons inspector Richard Spertzel told ABCNEWS.
But officials cautioned that even if Iraq or renegade Iraqi scientists prove to be the source, it's a separate issue from who actually sent the anthrax through the mail.
"What you have to keep in mind is the difference between knowledge about what type of information you have to have to produce it, and who could have sent it," Fleischer said. "They are totally separate topics that could involve totally separate people. It could be the same person or people. It could be totally different people. The information does not apply to who sent it."
Experts say the bentonite discovery doesn't rule out a very well-equipped lab using the Iraqi technique. In fact, commercial spray dryers that Iraq used to produce its biological weapons were bought on the open market from the Danish subsidiary of a U.S. company for about $100,000 a piece.
Starting Thursday, FBI agents began asking company officials in Columbia, Md., if anyone suspicious in this country had recently acquired one of them. — Brian Ross, Christopher Isham, Chris Vlasto and Gary Matsumoto
Atta Met Iraqi Spy
Raising new questions about whether Saddam Hussein was involved in the Sept. 11 attacks, officials in the Czech Republic now confirm for the first time that a key hijacker met with an Iraqi intelligence agent in Prague.
Czech Interior Minister Stanislav Gross said Mohamed Atta, believed by U.S. investigators to be a ringleader of the hijackers, met an Iraqi diplomat shortly before the consul was expelled. Czech intelligence officials were troubled by Al-Ani's photographing of the Radio Free Europe building in the city.
"At this point we can confirm," Gross said, "Mohamed Atta made contact with Iraqi intelligence officer Ahmad Khalil Ibrahim Samir Al-Ani, who was expelled from the Czech Republic for conduct incompatible with his diplomatic status on April 22, 2001."
"The details of this contact are under investigation," Gross said.
The meeting took place on Atta's second known visit to Prague. A year earlier, on June 2, 2000, he had came to Prague from Germany by bus in the morning hours. The next day, Gross said, Atta left for the United States.
Iraq's Deputy Prime Minister Tariq Aziz had previously denied Al-Ani had any contact with Atta in Prague. In recent weeks, Minister Gross also had said there was no evidence to support Prague media reports citing Czech intelligence officials who said Atta had met Al-Ani.
The meeting, along with Iraq's stockpiles of biological weapons, have led some to question whether Atta — and Hussein — were not somehow behind the anthrax attacks in the United States.
"There are reports that one of the things that may have happened at that meeting was that [Atta] was given by the Iraqi some sample of anthrax," former U.N. weapons inspector Richard Butler told ABCNEWS. "We do not know if that is true. I believe it is something that should be investigated."
For his part, Gross would not give further details on the Atta meeting.
"At this point, neither I nor anyone else from the police or Czech intelligence services will provide any further information concerning this contact and [Atta's] stay and movement on the territory of the Czech Republic until the investigation is finished," he said.
This weekend, FBI agents in Florida were conducting anthrax tests on two cars Atta had owned. — Brian Hartman
Check back for continuous updates on the hunt for terrorists from ABCNEWS' worldwide investigative team.
FBI Under Fire
Critics of the FBI are saying agents may have missed some early clues that could have helped prevent the Sept. 11 attacks.
Weeks before the hijackings, the FBI received a CIA warning that two suspected terrorists had slipped into the United States. The FBI was unable to locate the two men, who ended up among the 19 hijackers.
They did, in August, arrest Zacarias Moussaoui, an Algerian man who aroused suspicions at a Minnesota flight school. But FBI headquarters denied the agents' request to obtain a warrant to search through the suspect's computer because before Sept. 11 the agents didn't have enough evidence he was part of a terrorist plan.
"If going into that computer would have helped to determine or detect what was about to happen, then it's absolutely essential that that goes forward, even if you end up forgoing a prosecution," former FBI Assistant Director Buck Revell said.
And what about sharing information? After the Sept. 11 attacks, police chiefs complained that they were given the FBI's terrorist watch list, but little more. The FBI was also criticized for what many viewed taking too long to conduct tests and interview witnesses in the first Anthrax cases in Florida and New York.
FBI Director Robert Mueller acknowledges, "There were some missteps early on."
Mueller, a career prosecutor who is the FBI's new director, comes from outside the bureau to lead it in the most challenging time in the agency's history.
Sen. Charles Grassly, a longtime FBI critic, says the director faces a tough task.
"Director Mueller has two wars to win, one on the outside against the terrorists, the other is with his own bureacracy," Grassley said. — John Miller
Italian Police Probe Man Found in Box
An extraordinary stowaway is under investigation in Italy.
Italian police are trying to learn why Rizk Amid Farid, a 43-year-old Egyptian arrested near Rome, would have been shipping himself across the Atlantic Ocean in a furnished box complete with a bed and toilet.
Farid was discovered late last week in a shipyard in the southern port of Gioia Tauro, where his Canada-bound ship was docked for five days. Authorities on the ground say port authority personnel discovered Farid after hearing strange noises coming from his container.
Crammed into the suspicious stowaway's box with him were two cellular phones, a satellite phone, a computer, cameras, many documents, and even a drill for making airholes.
Police believe he boarded the ship in Egypt and planned to travel all the way to Canada. But Farid, who was holding a Canadian passport, also had a plane ticket to fly from Rome to Toronto to Montreal. His seat on the flight, scheduled to leave last Friday, was confirmed.
Italian investigators say everything about Farid — his documents and claims about himself — appear to be either false or obscured. They have checked his stories with police in other countries — including Egypt, Canada and the United States — and believe none has panned out. Canadian investigators are further investigating the suspect's background.
Though police have not said they have any direct evidence tying Farid to terrorism, he is the first person to be arrested in Italy on the basis of a new counterterrorism law passed last week in the wake of the Sept. 11 attacks. Under the new law, he can be held for at least six months as investigators try to determine whether he is a terrorist.
A prosecutor said the stowaway had studied in Egypt and in North America to qualify as a commercial jet engine mechanic. Before leaving Egypt, however, he was believed to be working at a magazine distribution company. Investigators say he claimed to be "running away" from a powerful brother-in-law in Egypt and had traveled in the container for five days. — Ann Wise in Rome, Yael Lavie in London and Brian Hartman in Washington