What happened during the 2001 anthrax letter attacks in the United States?

In 2001, a series of letters containing anthrax spores were mailed to various media headquarters in New York and Florida, as well as to the offices of two U.S. senators. This act of biological terrorism resulted in five deaths and infected more than a dozen other individuals.12

The attacks caused widespread disruption, forcing the evacuation of congressional office buildings, media offices, and the office of the governor of New York, while incurring billions of dollars in decontamination and investigation costs.2

Following an extensive investigation, the Federal Bureau of Investigation concluded in 2010 that the letters were sent by a microbiologist who had previously worked within the U.S. Army’s biological defense program. The suspect, who had been named in the investigation, committed suicide in 2008. The use of such agents to kill and frighten civilians is a profound violation of human life and security, and it remains a critical focus for public health and biodefense efforts.21