The Evidence Trail
Documents List Essential Clues
Thursday, August 7, 2008
The key clues that led the FBI to Army scientist Bruce E. Ivins ranged from the infinitesimally small -- tiny bits of genetic coding on a single anthrax spore -- to items as ordinary as a time stamp on a building security pass.
The evidence trail also included small imperfections on a printed envelope and specks of fiber on cellophane tape. It documented Ivins's odd working hours during early fall of 2001 and his late-night visits to his Frederick lab around the time the deadly anthrax letters were mailed.
Each piece of evidence was circumstantial on its face. Yet together they made what Justice Department officials called a compelling case, pointing to a solitary suspect who took his own life last week as indictments were being prepared against him.
"Based upon the totality of the evidence we had gathered against him, we are confident that Dr. Ivins was the only person responsible for these attacks," U.S. Attorney Jeff Taylor said in releasing documents summarizing the FBI's case against the anthrax specialist.
The documents released yesterday shed new light on the strength of the DNA evidence linking Ivins to the anthrax attacks, revealing for the first time how FBI officials and their scientist partners were able to trace the attack strain to Ivins's lab.
Shortly after the 2001 anthrax attacks, the FBI began amassing one of the world's largest collections of anthrax bacteria, more than 1,000 samples acquired from labs and institutes around the world. But in 2005, aided by new techniques, bureau scientists narrowed their focus to just one variety: a sub-branch of the deadly Ames strain known as RMR-1029.
That strain, with its four unique genetic mutations, was known to be the one used in the bioterrorism attacks. Its creator, investigators soon learned, was Ivins, a relatively obscure vaccine specialist at the Army's medical research lab in Frederick.
Ivins had grown the first batch of RMR-1029 in 1997 and kept a flask of the bacteria locked up at the Army base. A handful of lab workers potentially had access to the flask, and eventually investigators were able to eliminate all of them as suspects in the anthrax case, except for one: Ivins.
"The spores used in the attacks were taken from that specific flask, regrown, purified, dried and loaded into the letters," Taylor said. "No one received material from that flask without going through Dr. Ivins."
The FBI's analysis of its 1,000 samples showed that only eight had the same mutations as spores used in the attacks. All were from the RMR-1029 batch, which was still kept in a protected storage suite in Building 1425 at the Fort Detrick Army base where Ivins worked.
"Dr. Bruce Ivins has unrestricted access to the suite and has been the sole custodian of RMR-1029 since it was first grown," stated an October 2007 affidavit unsealed yesterday.
The FBI determined that Ivins had shared samples of his RMR-1029 bacteria with as many as 15 other labs and institutes nationwide. But a second clue ruled out any of the other labs as the likely source of the attack strain, Taylor said.