I certainly wouldn't be writing any book about how Ivins is the definitive culprit.
You might not, but I certainly would.
In June of 2000, over a year before the anthrax attacks, Ivins planned to murder a former co-worker just because she went back to medical school. He couldn't cope with her leaving his lab.
That's the kind of nut that Ivins was. The anthrax attacks were just part of a long series of criminal acts - including burglaries and harassment of other women he knew.
And he did all of his crimes while working for the government.