The 2001 anthrax attacks in the United States, also known as Amerithrax from its Federal Bureau of Investigation (FBI) case name, occurred over the course of several weeks beginning on September 18, 2001, only a few days after the September 11 attacks. Letters containing anthrax spores were mailed to several news media offices and two Democratic U.S. Senators, killing five people and infecting 17 others. (A 2004 study however, has shown that the total number of harmed people should be raised to 68 [1].) The primary suspect was not publicly identified until 2008.

In mid-2008, the FBI narrowed its focus to Bruce Edwards Ivins, a scientist who worked at the government's biodefense labs at Fort Detrick in Frederick, Maryland. Ivins was told of the impending prosecution and on July 27 committed suicide, by an overdose of acetaminophen.[2]

On August 6, 2008, federal prosecutors declared Ivins to be the sole culprit of the crime.[3] Two days later, Sen. Charles Grassley and Rep. Rush Holt called for hearings into the DOJ and FBI's handling of the investigation.[4][5]

Tom Carey was inspector in charge of the FBI Amerithrax investigation from October 2001 to April 2002.

On the mailings of the letters,

"What we do have and what we do know is that the anthrax was mailed here in the United States; we know it was mailed from 10 Nassau Street, Princeton, New Jersey, from a mailbox. We know the flow of the mail flow, we know the dates that the letters were sent, and it would appear to many of us that have worked this investigation, that it’s much more consistent with someone being an American-born, and having some level of familiarity with the Princeton-Clinton New Jersey area versus a foreign operative coming into the U.S. and being able to successfully conduct such an attack."

On May 9, 2002, New Scientist published an article that reported:

'The DNA sequence of the anthrax sent through the US mail in 2001 has been revealed and confirms suspicions that the bacteria originally came from a US military laboratory. The data released uses codenames for the reference strains against which the attack strain was compared. The two reference strains that appear identical to the attack strain most likely originated at the US Army Medical Research Institute for Infectious Diseases at Fort Detrick (USAMRIID), Maryland. The new work also shows that substantial genetic differences can emerge in two samples of an anthrax culture separated for only three years. This means the attacker's anthrax was not separated from its ancestors at USAMRIID for many generations.'