Federal investigators cinched their case against alleged anthrax mailer Bruce E. Ivins after sophisticated genetic tests by a California firm helped them trace a signature mixture of anthrax spores, the Los Angeles Times has learned.

Well before the deadly 2001 anthrax mailings, Ivins, through his work as a government scientist, had combined anthrax spores obtained from at least one outside laboratory, people familiar with the evidence said.

With the help of leading outside geneticists and a fresh look at the evidence by a new team of street-savvy investigators, the FBI concluded in recent months that only Ivins could reasonably have perpetrated the crimes.

Ivins, 62, a senior microbiologist at the government’s elite biodefense research institute at Ft. Detrick, Md., died last Tuesday in an apparent suicide as federal prosecutors prepared to bring murder charges against him.


Records reviewed by The Times and interviews with people knowledgeable about the investigation provide new details about the trail of evidence that finally led to Ivins.

Since 1980, Ivins had specialized in developing vaccines against anthrax and other biological weapons. He experimented with animals, including monkeys, rabbits and guinea pigs.

Ivins had mixed spores shipped to Ft. Detrick from the Army’s Dugway Proving Ground in Utah, a facility operated by the Battelle Memorial Institute in Ohio, a private contractor that performs top- secret work for the CIA and other agencies.

By cross-referencing the dates when those spores were received and handled at Ft. Detrick, the FBI sharply narrowed the list of government employees with possible access to the material.


Instead of trying to trace anthrax that could have come from perhaps dozens of sources, investigators became convinced that it had to have originated at the U.S. Army Medical Research Institute of Infectious Diseases, or USAMRIID, located within Ft. Detrick, about 50 miles north of Washington.

“Now, all of a sudden, you can put a time frame on this material,” said one of the people familiar with the evidence. “By mixing the material from the separate institutions, [Ivins] provided what became a signature.”

With new analyses showing that the admixture of anthrax could not have come from anywhere in the world but Ft. Detrick, FBI agents plunged deep into Ivins’ history.

That history included a pattern of letter-writing to newspapers. In one he defended the safety of research conducted on anthrax at Ft. Detrick.


“The only way I can think of being seriously injured by anthrax or plague vaccine is to get plunked on the head by a vial of the stuff,” Ivins wrote in a letter published April 12, 1997, in the Frederick (Md.) News-Post.

Immediately after the 2001 mailings, the FBI had turned to Ivins and his Ft. Detrick colleagues to help them with initial analyses of the anthrax evidence recovered in their investigation.

As the investigation ground on, authorities enlisted colleagues of J. Craig Venter, founder of a Rockville, Md., institute that had helped map the human genome. Based on analyses performed at the Institute for Genomic Research, Venter said the culprit “almost had to be a government scientist.” The institute’s analysis was completed under contract to the FBI and the National Institute of Allergy and Infectious Diseases.

Venter said federal investigators within the last two years retrieved the anthrax evidence from the institute.


“FBI came in and took freezers and all the samples,” he said in an interview Sunday.

Ibis Biosciences, a company in Carlsbad, performed some of the most recent anthrax analysis. The company tells its clients, including the FBI, that its high-resolution anthrax genotyping kit provides analyses more advanced than any other technology worldwide.

In fact, the company’s test results buoyed FBI and Justice Department officials.

“Their capability is very sophisticated; it is faster and more elegant than what had been available,” said Randall S. Murch, a former FBI scientist who earlier served as an outside consultant to the bureau for the anthrax investigation.


Ibis provided its services to the anthrax investigation under a nondisclosure agreement with the FBI that bars company personnel from discussing their work without government authorization.

Ivins’ government work with the separate batches of dry powder anthrax was not widely known at USAMRIID. Two former top officials there told The Times in recent weeks that they had no idea until being contacted by a reporter that USAMRIID had received anthrax in either powder or wet form from Dugway or Battelle, whose own anthrax testing is done in Ohio.

The former officials noted that USAMRIID typically supplies live anthrax spores for use at the two outside facilities, not the other way around. As part of his government job, Ivins, a microbiologist, grew spores used for experiments, called “challenges,” on monkeys, rabbits and other animals at USAMRIID. He also occasionally prepared spores, in liquid or frozen form, for shipment to Dugway and Battelle.

The forensic analysis of the anthrax sent in the mailings had long posed a challenge to the FBI, whose in-house scientists were not equipped to decipher the potential origin of the material. Some of the first analysis was performed by Ivins and other scientists at USAMRIID; such efforts also were attempted at Battelle, but technicians there rendered some of the material forensically useless by first sterilizing it with steam, scientists told The Times. A spokesman for Battelle, T.R. Massey, declined earlier this year to discuss Battelle’s role.


Six years ago, Ivins acknowledged to an Army investigator his use of “Ames strain” anthrax spores obtained from Dugway.

“We currently use Ames spores prepared at Dugway Proving Ground in 1997 for our challenges,” Ivins told the investigator on May 10, 2002, as part of the Army’s investigation of his failure to report what he described as accidental spillages of anthrax spores near or within his office and other nonlaboratory areas at USAMRIID.

After he bleached those areas, in December 2001, Ivins kept it a secret for five months, according to what he told the Army. It also was in December 2001 that FBI agents began questioning potential suspects at Ft. Detrick, a development that former colleagues say may have driven Ivins to panic regarding whether powder from the mailings could be traced to him.

When he acknowledged his stealth bleaching to the Army in April 2002, Ivins said that he had not wanted to “cry wolf” and distract his colleagues, who along with him were helping the FBI to analyze anthrax powder and other materials being gathered in the criminal investigation.


Until federal officials make public the details of the evidence that they say establishes Ivins’ guilt, some former colleagues and outside skeptics say they will not be persuaded.

“The scientific community seems to be concerned that the FBI is going to blow smoke at us,” said David R. Franz, a former Army commander who led USAMRIID during part of Ivins’ tenure, in the late 1990s.

The FBI Sunday refused to comment on how it had focused on Ivins.

“As soon as the legal constraints barring disclosure are removed, we will make public as much information as possible,” said FBI Assistant Director John Miller. “We will do that at one time, in one place. We will do that after those who were injured and the families of those who died are briefed, which is only appropriate.”


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david.willman@latimes.com

Times researcher Janet Lundblad contributed to this report.