Army scientist Bruce Ivins committed suicide last week as prosecutors prepared to charge him with carrying out the deadly attacks. In the past week, haunting details about Ivins' mental health have emerged. Multiple U.S. officials told The Associated Press that Ivins was obsessed with Kappa Kappa Gamma, going back as far as his own college days at the University of Cincinnati when he apparently was rebuffed by a woman in the sorority.
But several holes in the case remain.
Some questions may be answered when documents related to the case are released. For others, the answers may be incomplete, even bizarre. Some may simply never be answered.
Some friends and former co-workers have expressed doubt that Ivins would have unleashed the deadly toxin. They questioned whether he could have converted the bacteria into a fine powder without anyone at the Ft. Detrick biological warfare laboratory noticing.
The FBI is expected to lay out much of its case for family members beginning Wednesday. Around that time, authorities are expected to ask a federal judge to unseal documents revealing how the FBI closed in on Ivins.
"We've been suffering for seven years," Patrick Hogan, son-in-law of anthrax victim Robert Stevens, said in a phone interview from his home in Palm Springs, Fla. "I'm just glad they finally found somebody."
Whether the documents will prove that they found the right person remains unclear.
The key to the investigation wasthat matched the anthrax that killed five people to a specific batch controlled by Ivins. It is unclear, however, how the FBI eliminated as suspects others in the lab who had access to the anthrax.
And then there's the question of motive. Authorities believe the attacks may have been a twisted effort to test a cure for the toxin. Ivins complained of the limitations of animal testing and shared in a patent for an anthrax vaccine. But for now, it's not clear what, if any, evidence bolsters that theory.
Investigators also can't place Ivins in Princeton, N.J., when the letters were mailed from a mailbox there. And the only explanation for why the married father of two might have made the seven-hour round trip is bizarre.
Authorities say Ivins wasand had secretly visited sorority buildings on several campuses. The Princeton mailbox was not far from the sorority office there.
Katherine Breckinridge Graham, a Kappa alumna who serves as an adviser to the sorority's Princeton chapter, said Monday she was interviewed by FBI agents "over the last couple of years" about the case. She said she could not provide any details about the interview because she signed an FBI nondisclosure form.
However, Graham said there was nothing to indicate that any of the sorority members had anything to do with Ivins.
Richard Schuler, attorney for anthrax victim Robert Stevens' widow, Maureen Stevens, said he will attend Wednesday's FBI briefing with a list of questions.
"No. 1 is, 'Did Bruce Ivins mail the anthrax that killed Robert Stevens?"' Schuler said, adding, "I've got healthy skepticism. It's good to be the skeptic. The bottom line is, we want to see this perpetrator brought to justice."