The 2001 anthrax attacks, also known as Amerithrax (a portmanteau of "America" and "anthrax", from its FBI case name), occurred in the United States over the course of several weeks beginning on September 18, 2001, one week after the September 11 attacks. Letters containing anthrax spores were mailed to several news media offices and to senators Tom Daschle and Patrick Leahy, killing five people and infecting seventeen others. Capitol police officers and staffers working for Senator Russ Feingold were exposed as well. According to the FBI, the ensuing investigation became "one of the largest and most complex in the history of law enforcement". They are the only lethal attacks to have used anthrax outside of warfare.
The FBI and CDC authorized Iowa State University to destroy its anthrax archives in October 2001, which hampered the investigation. Thereafter, a major focus in the early years of the investigation was bioweapons expert Steven Hatfill, who was eventually exonerated. Bruce Edwards Ivins, a scientist at the government's biodefense labs at Fort Detrick in Frederick, Maryland, became a focus around April 4, 2005. On April 11, 2007, Ivins was put under periodic surveillance and an FBI document stated that he was "an extremely sensitive suspect in the 2001 anthrax attacks". On July 29, 2008, Ivins died by suicide with an overdose of acetaminophen (paracetamol).
