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 Fort 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 Fort 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 Fort 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 Fort 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 Fort 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 Fort 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 Fort 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.