I actually agree with an NYT editorial:
None of the investigators’ major assertions, however, have been tested in cross-examination or evaluated by outside specialists. It is imperative that federal officials make public all of their data so independent experts can judge whether the mailed anthrax was indeed identical to Dr. Ivins’s supply and only that supply.
It is also critical for officials to explain more fully how they eliminated the many other people with access to the material. (emphasis added)
Because Dr. Ivins killed himself before he could be indicted, there will be no opportunity for an adversarial testing of the F.B.I.’s conclusions. The bureau, unfortunately, has a history of building circumstantial cases that seem compelling at first but ultimately fall apart.
Hatfill had odious associations with white supremacists, and this was leaked out to cast aspersions on him when he was the main 'person of interest' in the case. So excuse me if I'm a little skeptical when many of the the first things to come out about Ivins are of a similar nature.