Khalid Sheikh Mohammed and two accomplices, Walid Bin Attash and Mustafa al-Hawsawi, are expected to plead guilty at the military commission on the Guantanamo Bay base as soon as next week.
Officials at the Pentagon headquarters are tight-lipped about the agreement. However, according to The New York Times, which cites anonymous officials at the Pentagon, the terms include that the accused men will avoid the risk of the death penalty and instead be sentenced to life imprisonment. This is confirmed by letters from the US government sent to relatives of some of the victims.
The three men were arrested in 2003 and are being held at Guantanamo Bay. The protracted legal process has been affected by the question of whether the torture they were subjected to in the CIA's prison has affected the evidence.
The US agreement with the men comes over 16 years after the prosecution process for al-Qaeda's terrorist attacks began – and more than 20 years after terrorists hijacked commercial airliners and crashed them into the World Trade Center in New York and the Pentagon. Nearly 3,000 people died in the attacks.
A fourth plane was hijacked and steered towards Washington, but it crashed in Pennsylvania after the crew and passengers tried to storm the cockpit.
The attack triggered what the then-US President George W Bush called his "war on terrorism", which led to the US military invasions of Afghanistan and Iraq and many years of American operations elsewhere in the Middle East.
