The argument over the US anthrax attacks of 2001 looks set to continue, as politicians begin asking tough questions about the investigation.

US law enforcement agencies last week released their reasons for suspecting Bruce Ivins, a senior anthrax researcher for the US Army, as the long-sought mailer of powdered anthrax to US media outlets and Senators in 2001.

Ivins’s death late last month, ruled a suicide, means those arguments will not now be examined in a court of law. But senior US politicians are calling for investigation of the evidence, which consisted only of requests by the Federal Bureau of Investigation (FBI) to search Ivins’ property over the past year.

Senator Chuck Grassley of Iowa called for a “full and thorough vetting” of the claims, noting that “more than a hundred people” had access to the flask of anthrax spores that the FBI says genetically matched the spores used in the attacks.


Unanswered questions

Grassley wants to know how many samples of that batch were sent to other labs, and how the FBI ruled out other people who might have had access to them.

He wants details of the measurements of oxygen isotopes in the attack anthrax, which reportedly identified where it was grown, and why logs showing late work in Ivins’ lab before the mailings did not focus the investigation on Ivins earlier.

He also wants to know if there is video evidence that it was Ivins working those late-night sessions.

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