Bruce Edwards Ivins (April 22, 1946 – July 29, 2008) was an American microbiologist, vaccinologist, senior biodefense researcher at the United States Army Medical Research Institute of Infectious Diseases (USAMRIID), Fort Detrick, Maryland, and the key suspect in the 2001 anthrax attacks.  On Tuesday, July 29, 2008, he died of an overdose of Tylenol with codeine in an apparent suicide after learning that criminal charges were likely to be filed against him by the Federal Bureau of Investigation for an alleged criminal connection to the 2001 anthrax attacks. No formal charges were ever actually filed against him for the crime, and no direct evidence of his involvement has been uncovered.

At a news conference at the United States Department of Justice (DOJ) on August 6, 2008, FBI and DOJ officials formally announced that the Government had concluded that Ivins was likely to have been solely responsible for “the deaths of five persons, and the injury of dozens of others, resulting from the mailings of several anonymous letters to members of Congress and members of the media in September and October 2001, which letters contained Bacillus anthracis, commonly referred to as anthrax.” On February 19, 2010, the FBI released a 92-page summary of evidence against Ivins and announced that it had concluded its investigation. The FBI conclusions have been contested by many, including senior microbiologists, the widow of one of the victims, and several prominent American politicians. U.S. Senator Patrick Leahy (D-VT) who was among the targets in the attack, Senator Chuck Grassley (R-IA), former Senator Arlen Specter (R-PA), Representative Rush Holt (D-NJ), and Representative Jerrold Nadler (D-NY) all argued that Ivins was not solely responsible for the attacks.

The FBI subsequently requested a panel from the National Academy of Sciences to review its scientific work on the case. On May 15, 2011, the panel released its findings, which “conclude[d] that the bureau overstated the strength of genetic analysis linking the mailed anthrax to a supply kept by Bruce E. Ivins.” The committee stated that its primary finding was that “It is not possible to reach a definitive conclusion about the origins of the B. anthracis in the mailings based on the available scientific evidence alone.”