The 2001 anthrax attacks, also known as Amerithrax from its Federal Bureau of Investigation (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 containing anthrax spores were mailed to several news media offices and two Democratic U.S. Senators (Tom Daschle and Patrick Leahy), killing 5 people and infecting 17 others. According to the FBI, the ensuing investigation became "one of the largest and most complex in the history of law enforcement."[1]

A major focus in the early years of the investigation was a bio-weapons expert named Steven Hatfill, who was eventually exonerated. Another suspect, Bruce Edwards Ivins, 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."[2] On July 29, 2008, Ivins committed suicide with an overdose of acetaminophen.[3]

Investigation

A reward for information totalling $2.5 million is being offered by the FBI, U.S. Postal Service and ADVO, Inc.
Authorities traveled to six continents, interviewed over 9,000 people, conducted 67 searches and issued over 6,000 subpoenas. "Hundreds of FBI personnel worked the case at the outset, struggling to discern whether the Sept. 11 al-Qaeda attacks and the anthrax murders were connected before eventually concluding that they were not."[72] In September 2006, there were still 17 FBI agents and 10 postal inspectors assigned to the case, including FBI Special Agent C. Frank Figliuzzi who was the on-scene commander of the evidence recovery efforts.[citation needed]

Anthrax archive destroyed
The FBI and Centers for Disease Control and Prevention (CDC) both gave permission for Iowa State University to destroy the Iowa anthrax archive, and the archive was destroyed on October 10 and 11, 2001.[73]

The FBI and CDC investigation has been hampered by the destruction of a large collection of anthrax spores collected over more than seven decades and kept in more than 100 vials at Iowa State University, Ames, Iowa. Many scientists claim that the quick destruction of the anthrax spores collection in Iowa eliminated crucial evidence useful for the investigation.

Al-Qaeda and Iraq blamed for attacks
Immediately after the anthrax attacks, White House officials repeatedly pressured FBI Director Robert Mueller to prove that they were a second-wave assault by al-Qaeda following the September 11 attacks.

On August 1, 2008, the Associated Press reported that Bruce E. Ivins, 62, who worked for the past eighteen years at the government's bio defense labs at Fort Detrick, had apparently committed suicide. Ivins was a top U.S. biodefense researcher who worked at Ft. Detrick.

https://en.wikipedia.org/wiki/2001_anthrax_attacks