By Joby Warrick
Washington Post Staff Writer
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.
Investigators had recovered four envelopes used by the bioterrorist, and each was a pre-stamped, 6 3/4 -inch envelope that bore an image of an eagle in the upper right-hand corner. As it happened, the four envelopes also had a tiny printing defect.
While about 45 million such envelopes were made, only a small number had the printing defect, and all of them were sold at post offices in Virginia and Maryland, including the Frederick post office where Ivins rented a mailbox.
Eventually, Taylor said, investigators concluded that "the envelopes used in the mailings were very likely sold at a post office in the greater Frederick, Md. area."
Bureau investigators also connected the fictitious return address on the second round of anthrax letters -- the "Greendale School" of Franklin Park, N.J. -- to a charity well-known to Ivins. He had donated numerous times to a group called the American Family Association, which in 1999 had filed a lawsuit on behalf of parents at the Greendale Baptist Academy in Wisconsin in a dispute involving corporal punishment.
Ivins's unusual working habits around the time of the attacks provided another clue, documents show. After keeping relatively consistent working hours during the winter and spring of 2001, the scientist began spending far more time at his lab from mid-August to October of that year. The anthrax letters are believed to have been mailed in two batches, in September and October.
Time stamps from security logs showed Ivins making rare late-night visits to the B3 biosecurity chamber where the flask of RMR-1029 anthrax spores was kept. Ivins normally worked from 7:30 a.m. to 4:45 p.m., but records showed a string of weekend and after-hours visits in September and October of 2001. Often during these visits he would work until after midnight, when no other researchers would be present.
When asked about the strange schedule in 2005, Ivins could offer no explanation. He told investigators only that he worked late during those weeks "to escape" life at home.
The FBI was unable to find evidence of legitimate work Ivins performed during those visits.