While theories about the attacker have focused mainly on domestic loners and foreign states or terrorists, law enforcement officials are now also examining the possibility that the criminal may be a knowledgeable insider.
Asked if the Federal Bureau of Investigation was investigating American military and nonmilitary laboratories that have had the powdery anthrax strain used in the attacks and individuals associated with such centers, a law enforcement official replied, "Certainly." The official said, "We are aggressively investigating every possible lead and every possible avenue," adding it was logical.
Few details of the insider investigation are known. But federal agents are already interrogating people in the military establishment that replaced the old program for making biological weapons. The facilities for that effort, in western Maryland, are major repositories of the Ames strain of anthrax, the particularly virulent form that federal officials have identified as the type used in the attacks that killed five people.
Col. Arthur M. Friedlander, the senior research scientist at the Army's biodefense laboratory at Fort Detrick, Md., said in an interview on Friday that officials there were cooperating with federal investigators.
"They've asked us about personnel who had access," he said, speaking reluctantly.
"They didn't talk to me about my personal experience," said Colonel Friedlander, a physician and leading anthrax expert. "They asked me about other personnel."
He went on to dismiss the insider idea as improbable. Whoever made the killer anthrax, he said, "clearly knew what they were doing."
"But to make the leap that this came out of a government lab is somewhat large," he added.
He emphasized that no one in his organization, the Army Medical Research Institute of Infectious Diseases, a leader in developing germ defenses, even knew how to make dry anthrax, as was found in the letters used in the attacks. Instead, he said, scientists there used wet anthrax, which is far easier to make. It is used in developing vaccines and testing their effectiveness.
"We haven't had an offensive program for a long time," Colonel Friedlander said. Nobody at the Army's laboratory, he added, "has that kind of expertise."
A dozen or two American laboratories are said to have the Ames strain, though no one knows for sure because researchers over the decades have informally shared pathogens like anthrax. Military laboratories like the one at Fort Detrick, as well as military contractors, are central to the Ames network, as they have often pioneered the nation's research on vaccines and other defenses against germ weapons.
The United States began its military program to make germ weapons during World War II and over the decades developed many ways to spread many diseases. A top agent was anthrax, a gallon of which was strong enough to kill eight billion people. President Richard M. Nixon, after renouncing germ weapons in 1969, championed a global treaty that, starting in 1975, banned such arms.
Since the start of the anthrax attacks, federal officials, scientists and amateur sleuths have scrambled to identify the source. Some see the attacker as home-grown - perhaps a disaffected scientist or a militia group - while others discern a conspiracy by a state like Iraq or a foreign terrorist group. In the United States, there are probably scores of laboratories and contractors and hundreds of people who have access to essential anthrax ingredients and recipes.
The insider avenue of inquiry is consistent with the official profile of the suspect, released on Nov. 9 by the F.B.I. The profile describes a man with a strong interest in science who is comfortable working with hazardous material and has "access to a source of anthrax and possesses knowledge and expertise to refine it."
Separately, a private expert in biological weapons, Barbara Hatch Rosenberg, has recently published a paper contending that a government insider, or someone in contact with an insider, is behind the attacks.
Though not an expert on criminal profiling, Dr. Rosenberg, a molecular biologist at the State University of New York, has testified on biological weapons before Congress, advised Bill Clinton when he was president and made addresses to international arms control meetings, including one a few days ago in Geneva.
Law enforcement officials said Dr. Rosenberg's assertion might turn out to be well founded, though they emphasized that the investigation was still broadly based. One official close to the federal investigation called the Rosenberg theory "the most likely hypothesis."
Referring to her paper, the official said, "I might not have put it so strongly, but it's definitely reasonable."
Other analysts, including some scientists and experts in germ weapons, expressed more skepticism of the theory that it had to be an insider, contending that the skills and knowledge needed to produce the type of anthrax in this attack were widely available.
The paper laying out Dr. Rosenberg's thesis was distributed on Thursday by the Stockholm International Peace Research Institute, an arms control group. Dr. Rosenberg, who is chairwoman of an arms control panel at the Federation of American Scientists, a private group in Washington, has argued repeatedly that states, not individuals, tend to have the wherewithal to make advanced biological weapons. International treaties that prohibit that work, she believes, are thus critical.
Dr. Rosenberg contends that the Ames strain probably did not originate in 1980 or 1981, as is often asserted, but arose decades earlier and was used in the secret American program to make biological weapons.
She agrees with a conclusion, reached by some experts knowledgeable about the investigation, that the anthrax powder distributed in the attacks by letter was treated in a sophisticated manner so it floated easily, as was done in the old American offensive weapons program, unlike Colonel Friedlander's defensive program, which uses the wet anthrax.
"All the available information," she said, "is consistent with a U.S. government lab as the source, either of the anthrax itself or of the recipe for the U.S. weaponization process." Dr. Rosenberg contended that the anthrax used in the attacks either originated in the weapons program itself or was made by someone who had learned the recipe.
The killer, Dr. Rosenberg concludes, is "an American microbiologist who had, or once had, access to weaponized anthrax in a U.S. government lab, or had been taught by a U.S. defense expert how to make it. Perhaps he had a vial or two in his basement as a keepsake."
The paper, "A Compilation of Evidence and Comments on the Source of the Mailed Anthrax," dated Nov. 29, is based on interviews with federal and private experts, published reports and scientific articles.
Richard H. Ebright, a microbiologist at Rutgers University who has followed the anthrax case and has read the Rosenberg paper, said he found it provocative but unconvincing.
"This is one extreme in the theorizing," Dr. Ebright said. "There are elements that are reasonable, but elements that are not. I'm confident that she started with the insider conclusion and then selected the facts." Even so, he said, American foes seem likely to seize on the paper and amplify the provocative thesis.
"Every state that's hostile to the United States is going to pick up on this," Dr. Ebright said. "They'll say it was an orchestrated government attack, which I don't believe for a second. But you can see people believing it."
Dr. Rosenberg's theory is getting attention in Europe, where the environmental group Greenpeace Germany is citing it as credible.
An American official sympathetic to her thesis said the Ames strain might have come from a place other than a military laboratory.
"There are other government and contractor facilities that do classified work with access to dangerous strains," the official said. "But it's highly likely that the material in the anthrax letters came from a person or persons who really had great expertise. We haven't seen any other artifacts that point us elsewhere."
-------------- next part -------------- An HTML attachment was scrubbed... URL: <../attachments/20011202/94504e17/attachment.htm> -------------- next part -------------- A non-text attachment was scrubbed... Name: not available Type: image/gif Size: 199 bytes Desc: not available URL: <../attachments/20011202/94504e17/attachment.gif>
