In another letter to Stevens, Ivins feigned renewed outrage about Haigwood's supposed comments. "I have personally gotten into several arguments about hazing with fraternity and sorority members, who have privately said that since I was not 'Greek' I had no right to criticize hazing," Ivins wrote Stevens on May 26, 1986, adding: "I wonder if only murderers have the right to criticize murderers, only Communists have the right to criticize Communists, only terrorists have the right to criticize terrorists."
His public self gave no hint of his private turmoil. Ivins appeared to lead a harmonious life: a successful scientist, married with two children and a home in a nice neighborhood. Yet over the years, he sought help from psychiatrists and counselors and was prescribed a battery of antidepressant and antipsychotic drugs.
A psychiatrist who treated him in the late 1990s, Dr. David Irwin, confided to a therapist that Ivins was the "scariest" patient he had ever known.
Army officials seemed oblivious to his instability — even if he was not. In emails to his current and former lab technicians, Ivins described disturbing thoughts and impulses and said he was struggling to control his behavior.
On July 18, 2000, Ivins told a mental health counselor that he had recently planned to poison his former assistant, Mara Linscott. In addition to having cyanide, he said that he had once obtained ammonium nitrate, to make a bomb.
He saw himself, Ivins said, as an "avenging angel of death."
After the anthrax letters were mailed in September and October of 2001, the FBI for nearly five years pursued a former Army virologist, Steven Hatfill, as the prime suspect.
Hatfill had filled several prescriptions in 2001 for Cipro, an antibiotic effective against anthrax, among other infections. He had also boasted of his expertise in biological warfare.
Based on this and other information, inspector Richard Lambert, handpicked by FBI Director Robert S. Mueller III to lead the investigation, was convinced that Hatfill was the perpetrator. With Mueller's backing, he drove his agents to find evidence to support an indictment against Hatfill. It never came.
On June 5, 2006, a visiting team of FBI employees arrived at the bureau's Washington Field Office for a long-scheduled audit of its general efficiency and effectiveness. A growing number of investigators were frustrated by Lambert's emphasis on Hatfill. They had felt powerless to do anything about it. Until now.
In a confidential report, the inspection team said more than 90% of the investigators on the anthrax case believed Lambert was concentrating on Hatfill to the exclusion of all other potential suspects. Lambert said the focus was never on one individual, exclusively.
In September 2006, Mueller replaced Lambert with two agents who had extensive backgrounds in criminal investigation, Edward Montooth and Vincent Lisi. A case that had foundered for years was reoriented: Investigators were told to focus on people who had verifiable access to a research batch of anthrax that geneticists had matched to the material used in the letter attacks.
On the Friday before Christmas 2006, Montooth and Lisi went to FBI headquarters for a briefing with the director.
"You've been there three months," Mueller reminded Montooth. "What's going on?"
Trying his best to keep expectations modest, Montooth let Mueller in on some news: "There's a guy that we can't wash out, no matter what we're doing. It makes us more suspicious."
The object of suspicion was an Army microbiologist who had created the batch of anthrax that matched the material in the letters. He had unrestricted access to this batch, and he had put in unusually long, solitary hours at the biocontainment lab, or "hot suite," at USAMRIID during the nights leading up to the mailings.
His name, Montooth said, was Bruce Ivins.
On the evening of Wednesday, July 9, 2008, Ivins arrived at Comprehensive Counseling Associates in Frederick, Md., for his weekly group therapy session. He was noticeably agitated. FBI agents had by now questioned him at length, and his lawyers expected he could soon be charged with murder in connection with the anthrax mailings.
When it was his turn to speak, Ivins, 62, said he was angry at the investigators and at the system that had dealt him this hand. He had a bulletproof vest and was going to obtain a new Glock handgun, he said. He had a list of people he was planning to kill.
"I'm not going to go down for five capital murders," he said. "I'm going to get them all."
The next day, police escorted Ivins out of Ft. Detrick, and he spent about two weeks at a psychiatric hospital near Baltimore before returning to his home in Frederick.
At 1:47 a.m. on Sunday, July 27, an ambulance rushed Ivins from his home to the emergency room at Frederick Memorial Hospital. He was comatose. Blood tests indicated a massive overdose of Tylenol. A few hours after he was admitted, Ivins showed responsiveness to those around him.
An intensive care nurse, Megan Shinabery, asked him: "Did you intentionally try to commit suicide?" Her handwritten notes reflect Ivins' response: "pt nodded yes."
Two days later, Ivins was dead.
On Aug. 6, 2008, eight days after his death, federal investigators announced that Ivins, acting alone, had perpetrated the anthrax mailings. Two days later, a prosecutor signed a letter to Steven Hatfill's lawyer, exonerating his client of any wrongdoing. The government paid Hatfill a $5.82-million legal settlement.
Photos: Bruce Ivins and the anthrax killings