A leading army microbiologist suspected of being behind the anthrax mailings in the US in autumn 2001 has apparently committed suicide, it emerged yesterday – just as federal prosecutors were preparing to bring capital charges against him for the attacks, which killed five people and infected 17 others.
The death of Bruce Ivins, a 62-year-old research specialist at the government's biodefence laboratory in Maryland, 40 miles north of Washington, was first reported by the Los Angeles Times and confirmed by US officials. It may finally resolve a mystery which has persisted for almost seven years.
The attacks, in the form of letters containing anthrax spores, brought near panic to a country still in shock from the 11 September attacks, crippling the postal service and reinforcing the sense that another terrorist strike could come at any moment, under any guise.
The first letters, postmarked 18 September 2001 and containing anthrax spores, were addressed to various media organisations in New York and Boca Raton, Florida. Three weeks later two more letters, containing an even purer, finely milled weapons-grade anthrax, were despatched to the Capitol Hill offices of two senators, the majority leader at the time, Tom Daschle, and his Democratic colleague Patrick Leahy of Vermont. Both came with crudely written notes, ending with the words "Allah is Great".
Initially, it was assumed that al-Qa'ida, or even Saddam Hussein's Iraq, was responsible. But such was the quality of the anthrax in the second wave of letters that investigators switched their attention to biodefence scientists who alone had access to such material and the expertise to make it – and in particular those at Usamriid, the US Army Medical Research Institute for Infectious Diseases, at Fort Detrick in Maryland.
The prime suspect was for a long time Steven Hatfill, a colleague of Mr Ivins, whom the FBI named a "person of interest" as early as 2002. Mr Hatfill, however, denied all wrongdoing and countersued the FBI for invasion of privacy. A month ago, the government agreed a $5m (£2.5m) out-of-court settlement, in effect dropping the case.
With the exoneration of Mr Hatfill, attention focused on Mr Ivins, an 18-year veteran at Usamriid. As the net closed, Mr Ivins, whom colleagues said was a sensitive and "thin-skinned" person at the best of times, grew increasingly agitated. A few days ago he was told by investigators he was likely to face charges that might carry the death penalty.
According to the Los Angeles Times, he took an overdose of the drugs Tylenol and Codeine. Mr Ivins was taken to Frederick's Memorial Hospital where he died on 29 July. His brothers said that his death appeared to be suicide.
Yesterday, the FBI refused to comment on what remains an ongoing case – raising the possibility that other people might still be under investigation. But officials indicated that a final decision would be taken soon. If the case is closed, it would confirm that Mr Ivins was the sole suspect. But his motive, assuming he was responsible, is still a mystery. Mr Ivins had long been working on an anthrax vaccine, and there was speculation he had sent out the letters as a test of whether the vaccine worked. But he must have known the dangers involved. Nor is there a clear explanation for the choice of media targets (the first person to die was Robert Stevens, a British-born journalist at the offices of the National Enquirer supermarket tabloid in Boca Raton.)
The vaccine test theory was also challenged by co-workers of Mr Ivins. Dr Russell Byrne, who has spent 15 years at Usamriid, said his colleague had been "hounded" by aggressive FBI agents who raided his home twice. According to Dr Byrne, Mr Ivins had recently been forcefully removed from his job by local police on the grounds he had become a danger to himself and others, and earlier in July had been taken to hospital suffering from depression. Dr Byrne insisted that his colleague was not responsible for the attacks.
In terms of mystery and seeming lack of obvious motive, the anthrax affair has been compared to the Unabomber case, involving Theodore Kaczynski, the brilliant mathematician who sent letter bombs to various targets between 1978 and 1995, killing three people and wounding 23, before being arrested at a remote cabin in Montana.
But Kaczynski was a social radical who believed his actions were necessary to alert humanity to the dangers of high technology. Mr Ivins' career gives no such clues. He was born in Ohio and educated at the University of Cincinnati where he took a PhD in microbiology. In 2003 he and two colleagues at Fort Detrick were given the Pentagon's highest civilian award for their work on anthrax vaccine.