The investigation of the 2001 anthrax attacks ended as far as the public knew on July 29, 2008, with the death of Bruce Ivins, a senior biodefense researcher at the U.S. Army Medical Research Institute of Infectious Diseases in Fort Detrick, Md. Less than a week after his apparent suicide, the FBI declared Ivins to have been the sole perpetrator of the 2001 Anthrax attacks. The FBI [had] turned the pressure up on him, isolating him at work and forcing him to spend what little money he had on lawyers to defend himself. He became increasingly stressed. Then came his suicide (which, as Eric Nadler and Bob Coen show in their documentary The Anthrax War," was one of four suicides among American and British biowarfare researchers in past years). But there was still a vexing problem. Silicon was used in the 1960s to weaponize anthrax. Anthrax spores were coated with the substance to prevent them from clinging together so as to create a lethal aerosol. But since weaponization was banned by international treaties, research anthrax no longer contains silicon, and the [anthrax] at Fort Detrick contained none. Ivins, no matter how weird he may have been, had neither the set of skills nor the means to attach silicon to anthrax spores. If Ivins had neither the equipment or skills to weaponize anthrax with silicon, then some other party with access to the anthrax must have done it.