Chemical
& Engineering News
December 4, 2006
Volume 84, Number 49
pp. 47-54
Anthrax Sleuthing
Science
aids a nettlesome FBI criminal probe
by Lois R. Ember
It was a tense, unsettling time.
A mere week after the Sept. 11, 2001, terror attacks, anthrax-laced letters
began coursing through the mails on their way to several news organs and
two U.S. senators, delivering death to five and mayhem to a nation.
This first major act of bioterrorism
on U.S. soil triggered one of the largest, most complex, and costliest
investigations ever undertaken by the Federal Bureau of Investigation,
and still the person who mailed the letters remains at large.
This September, Joseph Persichini
Jr., acting assistant director of the FBI's Washington field office, acknowledged
the major, if unheralded, role science is playing in the probe. Yet the
FBI has said little about what science has revealed, citing the criminal
nature of the case as its reason. What scientific tidbits the public has
been fed come from media reports, and most of these have been incorrect
or incomplete.
Since finding an unopened anthrax
letter addressed to Sen. Patrick J. Leahy (D-Vt.) in late 2001 and the
letter's dramatic handover to scientists at Fort Detrick in Maryland, the
FBI has clamped down on information on the probe. The embargo has been
so tight that a former top military scientist who now works for a government
contractor tells C&EN that he was consulted before the Leahy letter,
but afterward, he could get no updates on progress being made even from
friends in the FBI.
Though massive resources have
been devoted to solving the case, many FBI critics attribute FBI's silence
to the fact that the probe initially was misdirected and is now stalled.
Inexplicably, that silence was
broken this August. Then, Douglas J. Beecher, a microbiologist in the FBI's
hazardous materials response unit, published a paper in Applied & Environmental
Microbiology, a well-respected but not well-known journal. It took the
media a month to publish accounts of Beecher's article, which they generally
interpreted as indicating that the FBI initially had misunderstood the
nature of the anthrax used in the attacks.
After reading those news accounts,
Rep. Rush Holt (D-N.J.), a member of the House Permanent Select Committee
on Intelligence, wrote the FBI, requesting that it brief the committee
on the status of the investigation. Assistant FBI Director Eleni P. Kalisch
summarily rejected Holt's request.
Kalisch said that briefing the
intelligence committee on a criminal investigation would be inappropriate.
She also said the FBI and the Justice Department had decided long ago to
stop briefing members of Congress after sensitive, classified information
found its way into media accounts citing congressional sources. A Holt
spokesman told C&EN the intelligence committee received "three limited
briefings in 2002 and 2003, and no committee member has ever been implicated
in leaks."
Angered by the FBI's refusal to
brief Congress, Sen. Charles E. Grassley (R-Iowa), in late October, blasted
the FBI's investigation for its "dead-ends" and "lack of progress." In
a letter to Attorney General Alberto R. Gonzales, Grassley listed a litany
of questions he wanted the department and the FBI to answer. He is still
awaiting answers.
Beecher's peer-reviewed paper
set off heated discussions not only in Congress but also in the arms control
community and among government and academic scientists. The seven-page
article chronicles the methodology the FBI used to uncover the Leahy letter,
which, because it was unopened, contained the most unadulterated powder
recovered from any letter.
What sparked debate was one paragraph
in the discussion section that a military analyst, who asked not to be
named because he still works with the FBI, says "clearly had nothing to
do with the content of the article."
The first anthrax-laced letter
destined for the Senate reached the office of former Sen. Thomas A. Daschle
(D-S.D.) and was opened by one of his aides on Oct. 15, 2001. That simple
act unleashed a fluffy light tan powder that wafted through the office
and traveled the air ducts to contaminate the entire Hart Senate Office
Building. Offices in the Hart building were evacuated, and eventually,
other Senate and House offices were shuttered as well. The work of Congress
came nearly to a standstill.
Five years later—after the FBI
had conducted more than 9,100 interviews and 67 searches and had issued
6,000 grand-jury subpoenas—the case remains unsolved. FBI Director Robert
S. Mueller III expects the case will eventually be solved. But the FBI's
critics agree with Daschle, who contends that "the investigation's trail
has gone cold."
In an Oct. 16 Washington Post
OpEd, Daschle alludes to the Beecher article and writes that questions
still "remain in the scientific community about the composition of the
anthrax and the level of technological expertise required to manufacture
it."
Given how easily the powder in
the Daschle letter aerosolized, government officials, military scientists,
and academic anthrax experts were quoted in the media as claiming the anthrax
spores in the letter had to have been "weaponized." That is, the spores
had to have been specially treated or processed—milled and coated with
an additive such as silica—to make them float in the air. But in his article,
Beecher, almost as an aside, dismisses this possibility.
In the paragraph that set the
scientific and arms control communities abuzz, Beecher writes: A "widely
circulated misconception is that the spores were produced using additives
and sophisticated engineering supposedly akin to military weapon production."
This is the FBI's first public
statement on the investigation since it began analyzing the material in
the Leahy letter and the first time the bureau has described the anthrax
powder. Beecher, however, provides no citation for the statement or any
information in the article to back it up, and FBI spokeswomen have declined
requests to interview him.
"The statement should have had
a reference," says L. Nicholas Ornston, editor-in-chief of the microbiology
journal. "An unsupported sentence being cited as fact is uncomfortable
to me. Any statement in a scientific article should be supported by a reference
or by documentation," he says.
Early news reports, replete with
unnamed sources, implied that the universe of potential suspects was fairly
narrow. The perpetrator of the attacks, the reports said, was likely to
have special technical skills and likely had access to highly contained
defense labs such as those operated by the U.S. Army Medical Research Institute
of Infectious Diseases (USAMRIID) in Maryland and the Army's Dugway Proving
Ground in Utah.
Because the anthrax powders proved
to be so deadly, the thinking was that the perpetrator had to have used
equipment, additives, and procedures that the Army had used to weaponize
biological agents in its offensive bioweapons program before President
Richard Nixon shut it down in 1969.
Several former government officials
and scientists, who asked for anonymity, say the early media accounts that
Beecher says mischaracterized the anthrax powders can be traced to the
government's struggle to deal quickly with an unsettling and unfamiliar
threat.
At an Oct. 29, 2001, White House
press briefing, Maj. Gen. John S. Parker, then-commanding general of the
Army's Medical Research & Materiel Command at Fort Detrick, said silica
had been found in the Daschle letter. Tom Ridge, then-director of the White
House Office of Homeland Security, at a briefing a few days earlier said
a binding agent had been used to make the anthrax powders.
As one of the former government
officials tells C&EN, "Those judgments were premature and frankly wrong."
At the height of the attacks, top government officials with no scientific
background received briefings from people who also were not scientists,
and "the nuances got lost," he explains.
Sometimes scientists misspoke
as well, as was the case with the Armed Forces Institute of Pathology.
AFIP studied the anthrax powder from the Daschle letter using energy dispersive
X-ray spectrometry, and a top AFIP scientist, Florabell G. Mullick, reported
the presence of silica in an AFIP newsletter. Yet, the spectrum AFIP released
shows a peak for the element silicon, not silicon dioxide (silica).
Harvard University molecular biologist
Matthew S. Meselson, who has consulted for the FBI on the anthrax probe,
dismisses these early statements as misunderstandings or misinterpretations
of the scientific studies conducted on the Daschle powder. "I don't know
of anybody with spore expertise who actually worked on the stuff who said
the spores were coated," he says. The FBI has never publicly claimed the
spores were coated with silica and, in fact, told members of Congress at
classified briefings that the spores were not coated, he says.
Meselson alerted the FBI to a
1980 microbiology paper that reports finding silicon in the spore coat
of Bacillus cereus, a cousin to Bacillus anthracis, the bacterium that
causes anthrax. The silicon AFIP detected might be a natural element of
the anthrax spore coat.
Although the FBI has released
no information on studies probing for the presence of silicon in the coat
of anthrax spores, and no studies have been published, Peter Setlow suspects
that such studies have been done. About two years ago, Setlow, a molecular
biologist at the University of Connecticut Health Center, was invited to
an FBI-organized meeting of spore specialists.
The explanation for mischaracterizing
the attack material is really quite simple, one of the former government
officials says. When the attacks occurred, "there was no systematic methodology
in place to evaluate a biological powder forensically." Initially, he says,
the studies were "done on the fly." And quite frankly, he says, "a lot
of people didn't know what they were looking for.
"The pace of the forensic investigation
ground to a halt," this official says, "because there was not a lot of
available expertise in the scientific toolbox."
Much of the material from the
Daschle letter was consumed by destructive tests that produced little useful
information, the official says. The government was understandably reluctant
to proceed with tests on the Leahy powder until a validated testing protocol
was developed, he explains.
So in December 2001, the FBI met
with experts selected by the National Academies for advice on how to deal
with the Leahy letter, a participant at that meeting says. Six NAS-vetted
scientists attended that one-day meeting at the FBI's Washington field
office and produced a flow chart, a scientific playbook on how to analyze
the powder to garner the most information. Whether that flow chart was
ever used is unknown.
The December meeting was among
the first of eight the FBI would eventually convene with scientists "to
develop a comprehensive analytical scheme for evaluating and analyzing
the anthrax evidence," the FBI's Persichini says. In fact, the "FBI has
held two outreach sessions in the past 18 months, and Beecher was present
at the first one," says Milton Leitenberg, an arms controls expert at the
University of Maryland.
Also in his paper, Beecher writes:
"Individuals familiar with the compositions of the powders in the letters
have indicated that they were comprised simply of spores purified to different
extents." His citation for this statement is a 2003 article that investigative
journalist Gary Matsumoto published in the news section of Science (302,
1492).
Meselson, who reviewed Beecher's
article for the FBI, was asked to assess scanning electron micrographs
of the anthrax powder. Early in 2002, he spent half a day at the FBI's
Washington field office and looked at "a large heap of electron micrographs"
of the powder from the Daschle letter.
"I saw no evidence of anything
except spores, no evidence of silica nanoparticles," Meselson says. "If
silica was present, I would have seen it, but nothing could have been purer
than what I saw," he insists. Though purified, the preparation "had not
been milled," he adds.
A government official who asked
not to be named says the FBI knew early on that the Daschle and Leahy powders
had a high concentration of spores. "But knowing the specific attributes
of the spores took a longer time," he explains.
A former top military scientist
speaking on background because his current employer has government contracts,
tells C&EN that he, too, "saw scanning electron micrographs" of the
powder from the Daschle letter. "I saw only spores and almost no rubbish
from the culture media." If the spores had been coated with silica, they
would have looked like doughnuts with large sugar particles on them, he
says. Instead, "the Daschle spores were clean doughnut holes with no sugars."
He also says, "I had never seen
a preparation that pure—1012 spores per gram—with no rubbish." Curious
about the purity of the spores, he contacted William C. Patrick III, who
had made bioweapons for the Army when the U.S. had an offensive program.
He says Patrick told him it was possible to get rid of nonspore material
by repeatedly washing the spores with water and spinning off the culture
debris into the supernatant.
This former military scientist
never saw the material from the Leahy letter and "heard nothing from the
FBI regarding the Leahy letter." So, even though he saw pure spores in
the electron micrographs of the Daschle powder he was shown, "It was never
clear to me whether the spores were coated or not, because I heard it both
ways."
Media reports had described the
material released when the Daschle letter was opened as looking like a
cloud of smoke. "I had always thought the spores had to be treated to get
them to fluff up as they did," he says.
Meselson, however, has another
theory. He believes that "if the spores are pure enough, they will be suspended
into air, they will fly." He builds his theory on the scientific scaffold
of triboelectricity, which, he notes, "aerosol physicists haven't considered."
Triboelectricity occurs, for example,
when combing your hair on a dry winter's day causes sparks to fly as electrons
move from hair to bind more tightly to the comb. In Meselson's theory,
all the purified spores carry the same electrical charge so they will fly
apart. And, he says, "you don't need much to fly into the air" to cause
harm.
Both Meselson and the former military
scientist agree that making the purified preparations didn't require an
expensive laboratory setup. As the military scientist says, "A simple facility"
is really all that's needed. "I have concluded that maybe the hardest part
is doing it safely so you don't hurt yourself. Some experience is needed,
but it's probably more an art than a science," he says.
Arms control expert Jonathan B.
Tucker, a Bosch Public Policy Fellow at the American Academy in Berlin,
says, "The use of the Ames strain, the purity of the spores, and the extreme
volatility of the material suggests that it was made by an individual with
a high degree of technical sophistication."
Other experts say Beecher's now
famous paragraph broadens the scope of potential suspects to include individuals
or small groups lacking the resources of large national programs. Rutgers
University microbiologist Richard H. Ebright, however, doesn't believe
that it does.
As Ebright points out, the anthrax
mailer had to have the "requisite microbiological and powder preparation
skills." But equally important, the perpetrator "had to have access to
the attack strain," which in all the letters was Ames.
Ebright admits that the pool of
persons with the required skills is large and many times "larger than the
pool of persons with access to the [Ames] strain." Prior to the Sept. 11,
2001, attacks, the Ames strain "was narrowly distributed," probably to
"no more than a dozen, certainly no more than 20 laboratories" worldwide,
he says. Labs possessing the strain were part of U.S. and allied biodefense
and intelligence programs, and the perpetrator "must have obtained the
attack strain" from one of these labs, he argues.
On Oct. 5, NBC Nightly News reported:
"Investigators tell NBC News that the water used to make [the anthrax spores]
came from a northeastern U.S., not a foreign, source." Ebright says, "This
information, if correct, would appear to narrow the field" of labs possessing
seed cultures of the Ames strain prior to Sept. 11, 2001.
As Ebright explains, "The intersection
between institutions in possession of the Ames strain prior to Sept. 11,
2001, and institutions in the northeastern U.S. would appear" to narrow
the likely source of the Ames strain to "two or three institutions: USAMRIID;
the University of Scranton; and, if one interprets 'northeastern' broadly,
Battelle Memorial Institute" in Columbus, Ohio. Battelle does classified
research for the Department of Defense. A University of Scranton scientist
was using "nucleic acid sequences to develop taxonomies of bioweapons agents,
a subject of interest to the Department of Defense," Ebright says.
"If the NBC report on the identification
of the water source is correct, it reflects further development of the
analytical approach" reported in articles published in 2003 on the use
of stable isotope analysis for microbe forensics, Ebright says. Those methods
applied to O and H can provide information about the water used for the
culture media, Ebright says.
In mid-to-late 2003, the FBI contracted
out some 20-odd studies of the culture media using isotopic analyses to
trace to a specific geographic area the water and nutrients used to grow
the anthrax. Yet, early in 2002, DNA sequencing of the anthrax taken from
the first anthrax victim conducted at the Institute for Genomic Research
and other genetic analyses pointed to USAMRIID as the origin of the Ames
strain.
The DNA sequencing work was published
in Science in 2002 and reported by the media. Also noted in media accounts
was the radiocarbon dating analyses by Lawrence Livermore National Lab
in June 2002 that found the Ames attack strain was cultured no more than
two years before the mailings.
In November 2002, FBI Director
Mueller announced that efforts were being made to "reverse engineer" the
mailed anthrax. News accounts in spring 2003 reported that the work was
being conducted by the Army's biodefense center at Dugway Proving Ground.
These news reports, naming no
sources, claimed that Dugway had successfully reproduced the anthrax powder
used in the attacks. Dugway, according to the media, concluded that the
attack material was made with simple methods and inexpensive equipment
and that the spores were not coated with an additive such as silica.
Daniel Martin, a microbiologist
in Dugway's Life Sciences Division, tells C&EN that Dugway was asked
"to produce materials to see how they compared with the materials the FBI
had in its possession." But, Martin says, Dugway did not reverse or back
engineer the attack powder. "Back engineering implies that you know exactly
what the material is and can replicate the material exactly, step by step."
That isn't what Dugway did, he says.
Instead, Martin says, Dugway used
the Leahy powder as the culture starter to "produce several different preparations
using different media, and different ways of drying and milling the preparation"
that the FBI could use for comparison purposes. Dugway, he says, never
analyzed the Leahy powder and did no comparative analyses between the preparations
made and the Leahy powder.
Indeed, by fall 2003, Michael
A. Mason, then-assistant director of FBI's Washington field office, is
quoted as saying that the FBI had not been able to re-create the process
used to make the anthrax attack material. Still, he said, the FBI had learned
enough to believe that the perpetrator had special expertise.
Leitenberg says a well-connected
former military scientist told him that Dugway was only able to produce
preparations containing "one-fifth the number of spores found in the Leahy
powder." This same military source also told Leitenberg that Battelle Memorial
Institute was also asked to back engineer the Leahy powder.
Back in 2003, Mason was not certain
whether the anthrax case would ever be solved. Even if there was no "successful
resolution," Mason said the investigation was "remarkable" because of the
scientific and analytical skills employed.
So why, three years after Mason's
public remarks and a pretty effective gag order, has the FBI chosen to
speak out through Beecher's article? It's possible that the FBI is confident
enough in the science "to set the record straight or to deflect ongoing
or anticipated criticism," one former government official speculates.
It is also possible that Beecher's
famous paragraph may be setting the groundwork for the FBI's defense in
the suit brought against it by Steven J. Hatfill, whom former attorney
general John D. Ashcroft called "a person of interest," the former official
says.
A former FBI laboratory official
says the FBI may have realized that the scientific evidence is pointing
to a different conclusion than initial speculation that the perpetrator
had to be associated with a national program. If so, "then it is very valuable
for a number of reasons to have the evidence published in a peer-reviewed
scientific journal, which gives it a measure of acceptance and credibility,"
he says.
To underscore his statement, the
FBI lab official points to "the Daubert standard for scientific evidence
and associated case law." This standard is a legal precedent by which federal
trial judges rule on the admissibility of evidence based on its relevance
and reliability (C&EN, Feb. 27, page 36).
Despite Mason's uncertainty three
years ago, the FBI now seems confident that the case eventually will be
solved. Writing in the Washington Post on Oct. 6, former State Department
intelligence analyst Kenneth J. Dillon says there are two possible reasons
for that confidence. One is that the FBI actually knows but lacks some
confirmatory evidence to nail the perpetrator. The other, he writes, is
embarrassment because "the evidence [the FBI might have] points to the
clandestine biowarfare program of a close ally as the anthrax source."
If NBC reported the science correctly
and the water used to make the anthrax did come from a northeastern U.S.
source, Dillon's second supposition falls apart.
Leitenberg says that "scientists
in the biodefense programs of several nations allied to the U.S. have frequently
expressed the suspicion that the U.S. government is embarrassed to identify
segments or individuals of the U.S. biodefense community as responsible
for the 2001 anthrax events."
The FBI is not talking about the
perpetrator and is saying very little publicly about the science it has
called upon in trying to solve the five-year-old case. What the public
has been told points to a U.S. biodefense facility as the source of the
attack strain of anthrax spores that were not specially treated or engineered
but were very pure—and very deadly.
Chemical & Engineering News
ISSN 0009-2347
Copyright © 2006 American
Chemical Society
Timeline
Chronology Of A
Biocrime
Sept. 17 or 18, 2001: Five anthrax
letters likely mailed from Trenton, N.J., and postmarked Sept. 8 arrive
at news organizations in New York and Florida. Only the letters addressed
to the New York Post and NBC News are recovered; the existence of the others
is inferred from the pattern of infection.
Oct 4: A photo editor at the National
Enquirer in Florida is confirmed to have inhalation anthrax, the first
known case in the U.S. since 1976.
Oct. 5: The photo editor dies,
the first of five fatalities in the anthrax attacks.
Oct. 6 to Oct. 9: Two more anthrax
letters are mailed from Trenton, postmarked Oct. 9.
Oct. 15: Letter to former Sen.
Thomas A. Daschle (D-S.D.) is opened and tests positive for anthrax; the
enclosed anthrax is described as a "fine, light tan powder."
Oct. 16 and 17: Senate and House
offices are closed.
Oct. 19: Tom Ridge, then director
of the White House Office of Homeland Security, tells the media that anthrax
spores found in the letters to the Enquirer, NBC News, and Daschle are
"indistinguishable," meaning they are from the same strain.
Oct. 21 and 22: Two Washington,
D.C., postal workers who handled anthrax letters die.
Oct. 25: Ridge updates the scientific
analysis of the anthrax samples, telling reporters that the anthrax from
the Daschle letter was "highly concentrated" and "pure" and that a binding
material was used. The Daschle spore clusters, he says, are smaller when
compared with the anthrax found in the letter delivered to the New York
Post. He describes the Post anthrax as coarser and less concentrated—"clumpy
and rugged"—than the Daschle anthrax, which he says is "fine and floaty."
Still, he says, the material from both samples is the same Ames strain
of Bacillus anthracis, the bacterium that causes anthrax.
Oct. 29: Maj. Gen. John S. Parker
at a White House briefing says silica was found in the Daschle anthrax
sample, and the anthrax spore concentration in the Daschle letter was 10
times that of the New York Post letter.
Oct. 31: A New York woman dies
of anthrax. Maj. Gen. Parker testifies before the Senate Subcommittee on
International Security, Proliferation & Federal Services about the
anthrax found in the Daschle letter.
Nov. 7: Ridge briefs the press
and dismisses bentonite as an additive for the anthrax spores in the Daschle
letter and says it is silicon. (Iraq supposedly used bentonite in weaponizing
anthrax.)
Nov. 16: FBI finds anthrax letter
addressed to Sen. Patrick J. Leahy (D-Vt.).
Nov. 21: A Connecticut woman dies
of anthax, the fifth and last person to die as a result of the anthrax
mailings.
Dec. 5: The Leahy letter is opened
at the U.S. Army Medical Research Institute of Infectious Diseases, a biodefense
facility, at Fort Detrick, in Frederick, Md.
Dec. 12: The Baltimore Sun reports
that the anthrax spores used in the attacks match those produced in small
amounts over the past 10 years by the Army's Dugway Proving Ground in Utah.
Dec. 16: DNA testing of the anthrax
spores in the Leahy letter shows them to be the Ames strain. The Washington
Post reports that the spores in the Daschle and Leahy letters are identical
to those produced at Dugway Proving Ground.
Aug. 6, 2002: Then-attorney general
John Ashcroft, on CBS's "The Early Show," calls Steven Hatfill "a person
of interest" in the FBI investigation. (Hatfill has never been charged
with the crime, and he is suing the Justice Department, the New York Times,
and others.)
August 2006: FBI scientist Douglas
J. Beecher publishes a paper in Applied & Environmental Microbiology
in which he strongly implies that the spores in the anthrax letters were
not produced with additives and were not specially engineered (that is,
weaponized).
Mixup
Army Error Leads
To Ames Strain Misnomer
The Ames strain—implicated in
the 2001 anthrax-laden letter attacks—is one of 89 strains of Bacillus
anthracis, the bacterium that causes anthrax. Although its name implies
an Iowa origin, the virulent strain was actually isolated from a sick cow
that died in Texas in 1980 and later misnamed by Army researchers working
in Maryland.
Confused? So were the scientists
at the U.S. Army Medical Research Institute of Infectious Diseases (USAMRIID)
at Fort Detrick, in Frederick, Md.
In 1981, the Army obtained the
strain as part of a collection sweep it had undertaken to obtain as many
B. anthracis strains as possible to help develop and test vaccines. The
microbe was actually cultured by the Texas Veterinary Medical Diagnostic
Laboratory, part of the Texas A&M University system, which then transferred
it to USAMRIID.
Following proper procedure, the
Texas veterinary lab shipped the culture to Maryland in a special container
supplied by the U.S. Department of Agriculture. The container's return
address was USDA's National Veterinary Services Laboratory in Ames, Iowa.
The strain remained unnamed for
four years. Then, after isolating it from the culture, USAMRIID scientists
dubbed it Ames in a research paper published in 1985.
The Ames strain became notorious
following the 2001 anthrax attacks. Seven anthrax-laced letters were mailed
to various media outlets and to two U.S. senators on Sept. 18, 2001, and
Oct. 9, 2001.
The Army never developed the Ames
strain as a weapon in its offensive biological weapons program, which President
Richard Nixon ended in 1969. The gold standard B. anthracis microbe for
U.S. bioweaponeers was the Vollum 1B strain. |