(dpa) - The US Justice Department Wednesday said it was convinced that a top government scientist who committed suicide last week was the sole person responsible for the deadly 2001 anthrax attacks that terrified the nation.
Bruce Ivins was set to be indicted last week for the anthrax-laced mailings, sent only weeks after the September 11, 2001, terrorist attacks. The department earlier Wednesday unsealed hundreds of court documents it believed proved that Ivins had sent the letters.
"We believe that, based on the evidence we have collected, we could prove his guilt to a jury beyond reasonable doubt," said Jeffrey Taylor, US attorney for the District of Colombia.
Ivins, 62, worked as an anthrax researcher at the government's elite bio-defence laboratory in Fort Detrick, Maryland. He had never been officially named as a suspect, but the court documents reveal that search warrants for his property were issued as early as October 2007.
The documents provided extensive details of the growing case against Ivins, who died last week of an overdose of prescription Tylenol mixed with codeine.
"We were able to prevent (Ivins) from harming anyone else. Unfortunately, we were unable to prevent him from harming himself," Taylor told reporters.
Letters containing anthrax spores were sent to media outlets and members of Congress in September and October 2001, killing five people and infecting dozens of others. Nobody has been charged in the seven-year investigation.
Robert Mueller, director of the Federal Bureau of Investigation (FBI), had a two-hour meeting Wednesday with family members and victims of the attacks to detail the findings of the case, which could be formally closed in the near future.
According to the court documents, at the time of the mailings, Ivins owned a "large flask of highly purified anthrax spores that possess certain genetic mutations identical to the anthrax used in the attacks."
The FBI said that new scientific breakthroughs were required to link the anthrax mailings to a single flask in Ivins lab. The link was only successfully established in 2005, four years after the attacks.
"We faced a weapon which we have never, ever faced before in our life," said Joseph Persichini of the FBI's Washington field office.
Ivins provided investigators with false samples of anthrax from his laboratory and could not provide an "adequate explanation" of his work at the lab on the nights the letters were sent, according to the documents.
Until last week, the only publicly known suspect in the anthrax case had been one of Ivins' colleagues. Steven Hatfill, who was cleared of any involvement, won a 5.8-million-dollar settlement from the Justice Department after his name was leaked to the media as a "person of interest."