Despite the FBI offering to release their evidence against Dr. Ivins, their case against him in the anthrax case still seems to be rather flimsy. At least to me, it seems that their entire case is based on him being eccentric and that he had access to the strain of anthrax used in the attacks.
He may or may not have been responsible, but I find it hard to conclude that Dr. Ivins was responsible. I know a lot of people who are as comparably eccentric (I'd say that would include me, and I can't conceive myself of hurting someone else). And with a hundred people also having had access to the same strain, the FBI hardly has a slam-dunk case. Even though there are plenty of cases where a hypothesis is strongly supported only in the context of the accumulated evidence, this doesn't look like one of them, despite claims to the contrary by the FBI.
Is there some public information that I'm missing? Maybe I missed a press release by the FBI that presents a strong case. Or is the FBI desperate to close the case only for political reasons? At least the science behind their claim that the strain of anthrax used in the attacks came from Fort Detrick sounds fascinating, although I don't have the competence to judge how strong it is.
Glenn Greenwald wrote an excellent summary of certain facts concerning the anthrax attack suspect that killed himself. It highlights the fact that most media claims concerning his instability comes from a social worker who isn't terribly credible, especially when everyone else had a very different impression of him. It strengthens my suspicion that Dr. Ivins, the suspect for the anthrax attack, was an innocent researcher on whom the pressure from the FBI investigation drove him to suicide. However, I don't think the investigation was the main impetus for his suicide; it's more probable that it had merely aggravated an already existing mood disorder. Even if the social worker was telling only the truth, it could easily have been due to a depression made worse by the investigation, rather than him being psychopathic from birth.
Of course, I'm rather removed from all the facts and the above is largely speculation, but I think it's most likely. It's still entirely possible that he was indeed the perpetuator of the attacks or that he was murdered in a way to look like suicide so that the case could be officially closed. In any case, all the evidence that has been made available to the public so far is purely circumstantial; the FBI would have to reveal really strong evidence to convince everyone that the case should be closed.