A new technology that can quickly distinguish between subtly different strains of anthrax might have been central to the FBI's investigation of the deadly anthrax letters that killed five people and sickened many more in the autumn of 2001.

The FBI has not disclosed how it drew a connection between the anthrax attacks and Bruce Ivins, a researcher at the Army's infectious disease lab at Fort Detrick in Frederick. Ivins killed himself last week as prosecutors prepared to indict him in the anthrax killings.

But news reports and government filings suggest that a new instrument developed by a California company might have played a key supporting role.

Stories published recently by the Los Angeles Times and The Wall Street Journal, relying in part on unnamed sources, said that investigators employing technology that was not available in 2001 were finally able to find a genetic link between the anthrax recovered from the bodies of victims and mixed spores Ivins reportedly had in his work space at Fort Detrick in 2001.

The Times, citing records and interviews, said the breakthrough analyses came from Ibis Biosciences of Carlsbad. Steven A. Hofstadler, vice president for research at Ibis, told The Sun yesterday that he could "neither confirm nor deny" that his company has assisted the FBI with the anthrax investigation.

But in 2007 filings with the U.S. Securities and Exchange Commission, Ibis described its "Ibis T5000," a $525,000 instrument used for, among other things, "anthrax genotyping. ... It can identify virtually all bacteria, viruses and fungi and provide information about drug resistance, virulence and strain types of these pathogens within a few hours."

Hofstadler said development began in 2001, funded by the U.S. Defense Advanced Projects Research Agency. "The challenge was how you can detect a biological weapon if you're not sure what it is you're looking for," he said.

Instead of looking for the DNA signatures of specific pathogens, such as anthrax, Ibis' approach was to look for nonspecific regions common to many DNA molecules. Because different pathogens, and even different strains of the same pathogen, will have slightly different DNA weights, the T5000 can identify each by its unique weight signature.

The first operational T5000 system went to the U.S. Army Medical Research Institute for Infectious Diseases - the lab at Fort Detrick where Ivins worked - in 2005.

frank.roylance@baltsun.com

Maryland weather blog: Frank Roylance on meteorology

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