But Ivins clearly knew investigators were closing in. His house had been under surveillance for a year, federal agents followed him wherever he went and he had been interviewed by investigators several times. Ivins had a history of mental illness, but the pressure led to a further decline in his condition, colleagues have said, to the point that he was hospitalized.
On July 9, Ivins was attending a group therapy session in Frederick. According to an affidavit released yesterday, he told the group he was a suspect in the anthrax investigation and that he was angry at the government and the investigators.
"He said he was not going to face the death penalty," the affidavit said, "but instead had a plan to kill co-workers and other individuals who had wronged him. He said he had a bulletproof vest, and a list of co-workers, and added that he was going to obtain a Glock firearm from his son within the next day, because federal agents are watching him and he could not obtain a weapon on his own."
He was admitted to a psychiatric wing of Frederick Memorial Hospital the next day. Shortly after he was released, on July 24, he took the overdose of Tylenol and codeine that killed him.
Yesterday, federal lawyers asked a judge in Washington to unseal search warrants and affidavits that spelled out their case, and FBI Director Robert S. Mueller III met with families of the anthrax victims and lawmakers to lay out the evidence against Ivins. One congressman who was briefed said that the presentation was "compelling" but that he was not convinced Ivins acted alone.
According to documents released, investigators traced the anthrax to Ivins' lab in 2005 using newly developed genetic mapping techniques. They concluded that all the anthrax used in the mailings that led to fatalities came from a single flask of anthrax spores known as RMR-1029.
That flask was "created and solely maintained by Dr. Ivins," said Jeffrey Taylor, U.S. attorney for the District of Columbia. "No one received material from that flask without going through Dr. Ivins. We thoroughly investigated every other person who could have had access to the flask, and we were able to rule out all but Dr. Ivins."
The time needed for that investigation explains why Ivins was not identified as the principal suspect until two years later, in 2007, Taylor said. There was "a tremendous amount of additional investigation that needs to take place to identify the universe of individuals who have access to that flask," he said. "We're talking about a large number of individuals, over 100, who potentially had access to this substance."
