who was behind 9/11

The 9/11 attacks were orchestrated by the Islamist extremist group al-Qaeda, led by Osama bin Laden. The operational planner was Khalid Sheikh Mohammed, who conceived the plan of using hijacked planes to attack targets in the United States. Nineteen hijackers, mostly Saudi nationals, carried out the attacks by hijacking four airliners. Osama bin Laden was the mastermind who provided the personnel, money, and logistical support, while Khalid Sheikh Mohammed was the tactical architect. The attacks led to the deaths of nearly 3,000 people and profound global consequences. Bin Laden was killed by U.S. forces in 2011, and Khalid Sheikh Mohammed was captured in 2003.