The FBI has recommended that the Justice Department close the investigation into the 2001 anthrax attacks that killed five people and sickened 17, and the department could make its decision as early as tomorrow, federal law enforcement sources tell ABC News.
The FBI believes it has a strong circumstantial case against Bruce Ivins, the scientist who killed himself last week who worked in a military lab at Fort Detrick that did research on the exact strain of anthrax used in the deadly attacks that terrorized a nation.
Envelopes used in the attacks are thought to have been purchased not far from Fort Detrick.
And agents believe there was compelling evidence that Ivins was dangerous.
Jean Duley, who had been Ivins' social worker in therapy sessions, was convinced he might try to kill her and others.
She recently went to court seeking protection from Ivins. During a hearing on the matter, she described a chilling July 9 group counseling session.
"He was extremely agitated, out of control," she said.
"He proceeded to describe to the group a very long and detailed homicidal plan and intention, that he had bought a vest, obtained a gun, a very detailed plan to kill his co-workers, because he was about to be indicted on capital murder charges," she added. "He was going to go out in a blaze of glory."
Duley's account is disturbing, yes, but a former FBI agent who worked the anthrax case urges caution about drawing final conclusions.
"Where are the real facts that this guy took anthrax from Fort Detrick, drove it presumably to Princeton [New Jersey], and at least, at more than one occasion, dropped it in the mail?" asked ABC News consultant Brad Garrett, who worked on the case before leaving the FBI. "Where is that evidence? And maybe they have it. Who knows what they have."
Ivins had been conducting unauthorized tests with anthrax, but had not told supervisors, a 2002 Army report found.
"It should have been a red flag, immediately," Garrett said. But it's unclear how the FBI treated that information, and Ivins was even allowed to consult on the case.
For a long time, some at the FBI were convinced that Fort Detrick biodefense researcher Steven Hatfill was the anthrax killer.
Despite constant FBI hounding, Hatfill maintained his innocence and eventually filed a lawsuit against the Justice Department, claiming his privacy had been invaded and that investigators had humiliated him. The department settled the case in June, agreeing to pay Hatfill nearly $6 million.
When the Justice Department made the announcement that effectively exonerated Hatfill, investigators waited for Ivins to react.
It was just weeks later that Ivins allegedly began making the threats Duley referred to in her court petition for protection.
Investigators had Ivins in their crosshairs. Sources close to the investigation say the FBI recently conducted new DNA tests, which indicated that anthrax samples taken from a division in the lab where Ivins had direct access matched anthrax lifted from the envelopes used in the attacks.
But as many 30 scientists may have had access to the area where the anthrax was stored in the lab, and given the missteps in the Hatfill case, some are reserving judgment until they see the complete array of evidence against Ivins.
Former Sen. Tom Daschle, one of the leaders of Congress targeted by the anthrax killer, is among the skeptics.