Anthrax Letters (2001)

The 2001 anthrax letters began appearing one week after the September 11 attacks, with contaminated envelopes sent to news media offices and Democratic senators. The letters contained weapons-grade Bacillus anthracis spores and messages referencing Allah and 9/11, initially suggesting Islamic terrorist involvement. Five people died from inhalation anthrax, including postal workers and media employees, while seventeen others were infected. The attacks caused widespread fear and disrupted mail service nationwide.

The FBI’s Amerithrax investigation became one of the largest and most complex in Bureau history, initially focusing on external terrorist groups before shifting to domestic suspects. Steven Hatfill, a biodefense researcher, endured years of public scrutiny and surveillance before being cleared in 2008. The investigation then centered on Bruce Ivins, a microbiologist at the U.S. Army Medical Research Institute of Infectious Diseases (USAMRIID), who committed suicide in July 2008 as prosecutors prepared charges against him.

The FBI concluded that Ivins acted alone, citing circumstantial evidence including his access to anthrax spores, unusual laboratory hours, and mental health issues. However, the case remains controversial among scientists and journalists who question the technical evidence linking Ivins to the letters. Critics note problems with the genetic analysis, the sophistication of the anthrax preparation, and gaps in the investigation’s timeline. The National Academy of Sciences found the FBI’s scientific conclusions were not fully supported by the evidence, though no alternative perpetrator has been credibly identified.