Immediately after the attacks, the FBI’s top job was to identify the attackers and prevent another incident. Experts in terrorism, evidence collection, and other specialties worked feverishly to determine what had happened and who was responsible. The FBI also coordinated with its partners in law enforcement and the intelligence community domestically and abroad as it launched its most ambitious investigation ever.
Within minutes, officials at FBI Headquarters in Washington, D.C., activated the Strategic Information and Operations Center. By the end of the day, the FBI had established command posts for each of the three crash sites.
Thousands of agents interviewed witnesses and sources. They tracked down clues and tips worldwide to determine what had happened, who did it, and how future acts could be prevented. The FBI started identifying the 19 terrorists within hours.
Then-FBI Director Robert S. Mueller, III broke with routine and based the massive investigation out of FBI Headquarters instead of a field office. The PENTTBOM Team—short for Pennsylvania, Pentagon, and Twin Towers Bombing—coordinated the investigation out of a basement office, where dozens of agents would build a case against those responsible.
The case, which remains open, revealed extraordinary acts of courage and selflessness among the spectrum of responders. And it forever changed the way the FBI works with law enforcement and intelligence community partners to keep Americans safe in the U.S. and abroad.
“Because of that terrible day, starting in 2001 under the leadership of Director Mueller, the FBI transformed itself in ways that have made us stronger and better—and our country safer,” Director Christopher Wray said in 2019 during a visit to the National September 11 Memorial & Museum in New York City.