How many people were killed by the 2001 anthrax attacks?

The 2001 anthrax attacks, also known as Amerithrax from its FBI case name, occurred within the United States over the course of several weeks beginning on September 18, 2001, one week after the September 11 attacks. Letters were mailed containing anthrax spores to several news media offices and to Democratic Senators Tom Daschle and Patrick Leahy, killing 5 people and infecting 17 others. A copycat hoax letter containing harmless white powder was opened by reporter Judith Miller in The New York Times newsroom. According to the FBI, the ensuing investigation became "one of the largest and most complex in the history of law enforcement".

A major focus in the early years of the investigation was bioweapons expert Steven Hatfill, who was eventually exonerated. Another suspect was Bruce Edwards Ivins who became a focus of investigation around April 4, 2005. Ivins was a scientist who worked at the government's biodefense labs at Fort Detrick in Frederick, Maryland. On April 11, 2007, Ivins was put under periodic surveillance and an FBI document stated that "Bruce Edwards Ivins is an extremely sensitive suspect in the 2001 anthrax attacks." On July 29, 2008, Ivins committed suicide with an overdose of acetaminophen.