The Anthrax Attacks: An Essential Prologue to the Preceding Post

The Anthrax Attacks Remain Unsolved
The FBI disproved its main theory about how the spores were weaponized.

By EDWARD JAY EPSTEIN

The investigation of the 2001 anthrax attacks ended as far as the public knew on July 29, 2008, with the death of Bruce Ivins, a senior biodefense researcher at the U.S. Army Medical Research Institute of Infectious Diseases (USAMRIID) in Fort Detrick, Md. The cause of death was an overdose of the painkiller Tylenol. No autopsy was performed, and there was no suicide note.

Less than a week after his apparent suicide, the FBI declared Ivins to have been the sole perpetrator of the 2001 Anthrax attacks, and the person who mailed deadly anthrax spores to NBC, the New York Post, and Sens. Tom Daschle and Patrick Leahy. These attacks killed five people, closed down a Senate office building, caused a national panic, and nearly paralyzed the postal system.

The FBI's six-year investigation was the largest inquest in its history, involving 9,000 interviews, 6,000 subpoenas, and the examination of tens of thousands of photocopiers, typewriters, computers and mailboxes. Yet it failed to find a shred of evidence that identified the anthrax killer—or even a witness to the mailings. With the help of a task force of scientists, it found a flask of anthrax that closely matched—through its genetic markers—the anthrax used in the attack.

This flask had been in the custody of Ivins, who had published no fewer than 44 scientific papers over three decades as a microbiologist and who was working on developing vaccines against anthrax. As custodian, he provided samples of it to other scientists at Fort Detrick, the Battelle Memorial Institute in Columbus, Ohio, and other facilities involved in anthrax research.

According to the FBI's reckoning, over 100 scientists had been given access to it. Any of these scientists (or their co-workers) could have stolen a minute quantity of this anthrax and, by mixing it into a media of water and nutrients, used it to grow enough spores to launch the anthrax attacks.

Consequently, Ivins, who was assisting the FBI with its investigation, as well as all the scientists who had access to the anthrax, became suspects in the investigation. They were intensely questioned, given polygraph examinations, and played off against one another in variations of the prisoner's dilemma game. Their labs, computers, phones, homes and personal effects were scrutinized for possible clues.

As the so-called Amerithrax investigation proceeded, the FBI ran into frustrating dead ends, such as its relentless five-year pursuit of Steven Hatfill, which ended with an apology in 2007 and Mr. Hatfill receiving a $5.8 million settlement from the U.S. government as compensation. Another scientist, Perry Mikesell, became so stressed by the FBI's games that he began to drink heavily and died of a heart attack in October 2002.

Eventually, the FBI zeroed in on Ivins. Not only did he have access to the anthrax, but FBI agents suspected he had subtly misled them into their Hatfill fiasco. A search of his email turned up pornography and bizarre emails which, though unrelated to anthrax, suggested that he was a deeply disturbed individual.

The FBI turned the pressure up on him, isolating him at work and forcing him to spend what little money he had on lawyers to defend himself. He became increasingly stressed. His therapist reported that Ivins seemed obsessed with the notion of revenge and even homicide. Then came his suicide (which, as Eric Nadler and Bob Coen show in their documentary "The Anthrax War," was one of four suicides among American and British biowarfare researchers in past years). Since Ivins's odd behavior closely fit the FBI's profile of the mad scientist it had been hunting, his suicide provided an opportunity to close the case. So it held a congressional briefing in which it all but pronounced Ivins the anthrax killer.

But there was still a vexing problem—silicon.

Silicon was used in the 1960s to weaponize anthrax. Through an elaborate process, anthrax spores were coated with the substance to prevent them from clinging together so as to create a lethal aerosol. But since weaponization was banned by international treaties, research anthrax no longer contains silicon, and the flask at Fort Detrick contained none.

***

Yet the anthrax grown from it had silicon, according to the U.S. Armed Forces Institute of Pathology. This silicon explained why, when the letters to Sens. Leahy and Daschle were opened, the anthrax vaporized into an aerosol. If so, then somehow silicon was added to the anthrax. But Ivins, no matter how weird he may have been, had neither the set of skills nor the means to attach silicon to anthrax spores.

At a minimum, such a process would require highly specialized equipment that did not exist in Ivins's lab—or, for that matter, anywhere at the Fort Detrick facility. As Richard Spertzel, a former biodefense scientist who worked with Ivins, explained in a private briefing on Jan. 7, 2009, the lab didn't even deal with anthrax in powdered form, adding, "I don't think there's anyone there who would have the foggiest idea how to do it." So while Ivins's death provided a convenient fall guy, the silicon content still needed to be explained.

The FBI's answer was that the anthrax contained only traces of silicon, and those, it theorized, could have been accidently absorbed by the spores from the water and nutrient in which they were grown. No such nutrients were ever found in Ivins's lab, nor, for that matter, did anyone ever see Ivins attempt to produce any unauthorized anthrax (a process which would have involved him using scores of flasks.) But since no one knew what nutrients had been used to grow the attack anthrax, it was at least possible that they had traces of silicon in them that accidently contaminated the anthrax.

Natural contamination was an elegant theory that ran into problems after Congressman Jerry Nadler pressed FBI Director Robert Mueller in September 2008 to provide the House Judiciary Committee with a missing piece of data: the precise percentage of silicon contained in the anthrax used in the attacks.

The answer came seven months later on April 17, 2009. According to the FBI lab, 1.4% of the powder in the Leahy letter was silicon. "This is a shockingly high proportion," explained Stuart Jacobson, an expert in small particle chemistry. "It is a number one would expect from the deliberate weaponization of anthrax, but not from any conceivable accidental contamination."

Nevertheless, in an attempt to back up its theory, the FBI contracted scientists at the Lawrence Livermore National Labs in California to conduct experiments in which anthrax is accidently absorbed from a media heavily laced with silicon. When the results were revealed to the National Academy Of Science in September 2009, they effectively blew the FBI's theory out of the water.

The Livermore scientists had tried 56 times to replicate the high silicon content without any success. Even though they added increasingly high amounts of silicon to the media, they never even came close to the 1.4% in the attack anthrax. Most results were an order of magnitude lower, with some as low as .001%.

What these tests inadvertently demonstrated is that the anthrax spores could not have been accidently contaminated by the nutrients in the media. "If there is that much silicon, it had to have been added," Jeffrey Adamovicz, who supervised Ivins's work at Fort Detrick, wrote to me last month. He added that the silicon in the attack anthrax could have been added via a large fermentor—which Battelle and other labs use" but "we did not use a fermentor to grow anthrax at USAMRIID . . . [and] We did not have the capability to add silicon compounds to anthrax spores."

***

If Ivins had neither the equipment or skills to weaponize anthrax with silicon, then some other party with access to the anthrax must have done it. Even before these startling results, Sen. Leahy had told Director Mueller, "I do not believe in any way, shape, or manner that [Ivins] is the only person involved in this attack on Congress."

When I asked a FBI spokesman this month about the Livermore findings, he said the FBI was not commenting on any specifics of the case, other than those discussed in the 2008 briefing (which was about a year before Livermore disclosed its results). He stated: "The Justice Department and the FBI continue working to conclude the investigation into the 2001 anthrax attacks. We anticipate closing the case in the near future."

So, even though the public may be under the impression that the anthrax case had been closed in 2008, the FBI investigation is still open—and, unless it can refute the Livermore findings on the silicon, it is back to square one.

Mr. Epstein is currently completing a book on the 9/11 Commission.

The Anthrax Attacks: Yet Another Major 9/11 Mystery Left Unaddressed in an Official Report Fingering a Perpetrator Not Around to Defend Himself

Blogger's Note: This article and the figure below are both reproduced unaltered from a "News of the Week" article in the 19 March 2010 issue of Science, the prestigious journal of the American Association for the Advancement of Science.  However, I have taken the liberty of placing a quote from the article immediately below the figure.

The unusually high percentage of silicon-bearing spores in the attack material "is a bit of a strange thing," says Michael. "We have no way of knowing how they were really grown." An anthrax researcher who did not wish to be named calls it "awfully weird" and "a particularly inconvenient exception" because it leaves a gap in the case.

Science 19 March 2010:
Vol. 327. no. 5972, p. 1435
DOI: 10.1126/science.327.5972.1435

ANTHRAX INVESTIGATION:
Silicon Mystery Endures in Solved Anthrax Case
Yudhijit Bhattacharjee

What about the silicon?

That question has confounded investigators throughout the probe into the 2001 anthrax letter attacks, which the U.S. government formally concluded in February. Scientists inside and outside the government say there is clear evidence that the high levels of silicon found in the anthrax came not from anything added to "weaponize" the anthrax spores—as researchers had suggested early in the probe—but from the culture in which the spores were grown. That evidence may have settled the issue of whether the anthrax was weaponized, at least for scientists familiar with the case. But it raises a different question: Why did the mailed anthrax have such a high proportion of spores with a silicon signature in comparison to most other anthrax samples?

The answer, according to academic scientists who helped with the case, probably would not change the FBI's conclusion that the attacks were the sole handiwork of now-deceased U.S. Army researcher Bruce Ivins. But it could help illuminate exactly how the attack material was prepared. Resolving the mystery might also pave the way for new techniques using trace elements in a bioterrorism agent to link it to its source.

"There's tremendous interest in using metal signatures as a forensic tool," says Adam Driks, an anthrax researcher at Loyola University Chicago in Illinois. But the science to do that is lacking: "We know very, very little about the diversity of elemental composition within spores when they are produced in different ways."

The FBI's scientific case against Ivins rests on DNA tests showing that the mailed anthrax came from a flask under Ivins's control at the U.S. Army Medical Research Institute of Infectious Diseases in Frederick, Maryland. Investigators also had the attack material chemically analyzed, first at the Armed Forces Institute of Pathology (AFIP) in Washington, D.C., within weeks of the attack. Examining the spores under a scanning electron microscope, AFIP scientists detected silicon and oxygen and concluded that the spores had been coated with silica to make them float easily, enhancing their power to kill.

A more detailed analysis by Joseph Michael and Paul Kotula of Sandia National Laboratories in Albuquerque, New Mexico, contradicted that conclusion. Studying individual spores with a transmission electron microscope, they found that the silicon was located within the spore coat, well inside the cell's exosporium (outermost covering). By contrast, when they looked at surrogate spores weaponized with silica, the silicon was clearly outside the exosporium.

But the Sandia study, presented last September to a National Academies panel reviewing the science behind the investigation, still leaves questions. Out of 124 spores from a letter mailed to Senator Patrick Leahy of Vermont, Michael found the silicon-and-oxygen signature in 97—78% of the sample. The signature was present in 66% of a sample from a letter to former Senator Tom Daschle and in 65% of spores from a letter sent to the New York Post.

Out of nearly 200 other anthrax samples from different labs, none came close to displaying such a prominent silicon signature. The highest, in a sample from Dugway Proving Ground in Utah, was 29%. The researchers couldn't find silicon in the coat of a single spore out of some 300 taken from RMR-1029, the flask in Ivins's lab identified as the source of the bacteria used in the attacks; they concluded that all the silicon had come from the culture.

The unusually high percentage of silicon-bearing spores in the attack material "is a bit of a strange thing," says Michael. "We have no way of knowing how they were really grown." An anthrax researcher who did not wish to be named calls it "awfully weird" and "a particularly inconvenient exception" because it leaves a gap in the case. However, neither scientist thinks the anomaly casts doubt on the broader investigation.

The key to the mystery likely lies in the culture medium the perpetrator used to grow the anthrax spores, says Michael. In a recent study, Japanese researchers grew colonies of Bacillus cereus—a close relative of the anthrax bacterium, B. anthracis—in culture media with and without added silicate. Spores grown in the silicate-containing culture showed silicon within the spore coat. In the absence of silicate, there was no silicon, the group reported in January in the Journal of Bacteriology.

One of the study's authors, microbiologist Akio Kuroda of Hiroshima University in Japan, says the precise amount of silicon in individual spores from the anthrax letters could offer clues about the medium. "If the anthrax spores contained a high amount, the suspect must have used a medium that was supplemented with silicon or that intrinsically contained a lot of silicon," Kuroda says. "If a thorough testing of various media sold in the U.S. identifies a few that contain higher amounts of silicon, those could become an investigative clue."