“Paranoid man works with deadly anthrax!!!” he wrote in one e-mail message in July 2000, predicting what a National Enquirer headline might read if he agreed to participate in a study on his work.

“I wish I could control the thoughts in my mind,” he added a month later in another message to a colleague. “It’s hard enough sometimes controlling my behaviour. When I am being eaten alive inside, I always try to put on a good front here at work and at home, so I don’t spread the pestilence.”

He continued, “I get incredible paranoid, delusional thoughts at times, and there’s nothing I can do until they go away.”

These e-mail messages and dozens of others are a central element in the case the Federal Bureau of Investigation laid out on Wednesday against the man they say is responsible for the anthrax attacks that killed five people and panicked the country. They provide glimpses into the personality of a man obsessed with a sorority that he first encountered while an undergraduate, asserting in an e-mail message that the women’s group was waging a “fatwah” against him.

Ivins composed poems— scripted to the nursery rhymes “Hickory Dickory Dock” and “I’m a Little Teapot— about having two personalities. And he went on what he called “mindless drives” to mail gifts and letters anonymously, the document said, and then “set back the odometer in his car” to fool his wife.

Ivins’s friends and family had argued that his suicide last week and proceeding mental decline was provoked by being the target of FBI investigators who questioned his family and followed his every move in the last year. But the records released on Wednesday make it clear that . Ivins, a microbiologist who worked at the United States Army Medical Research Institute of Infectious Diseases at Fort Detrick, Md., had suffered from mental problems long before.

None of the e-mail, his lawyers point out in asserting their former client’s innocence, ever threatened a biological attack or acknowledged responsibility for one. The messages do, however, show that Ivins privately confided to an unidentified co-worker that he was deeply troubled.

A forensic psychiatrist consulted by the FBI found that Ivins had been treated with antidepressants and anti anxiety and antipsychotic medication, according to the documents.