Accused Sept. 11 Plotters Agree to Plead Guilty at Guantánamo Bay

The man accused of plotting the attacks of Sept. 11, 2001, and two of his accomplices have agreed to plead guilty to conspiracy and murder charges in exchange for a life sentence rather than a death-penalty trial at Guantánamo Bay, Cuba, prosecutors said Wednesday.

Prosecutors said the deal was meant to bring some “finality and justice” to the case, particularly for the families of nearly 3,000 people who were killed in the attacks in New York City, at the Pentagon and in a Pennsylvania field.

The defendants Khalid Shaikh Mohammed, Walid bin Attash and Mustafa al-Hawsawi reached the deal in talks with prosecutors across 27 months at Guantánamo and approved on Wednesday by a senior Pentagon official overseeing the war court.

The men have been in U.S. custody since 2003. But the case had become mired in more than a decade of pretrial proceedings that focused on the question of whether their torture in secret C.I.A. prisons had contaminated the evidence against them.

Word of the deal emerged in a letter from war court prosecutors to Sept. 11 family members.

“In exchange for the removal of the death penalty as a possible punishment, these three accused have agreed to plead guilty to all of the charged offenses, including the murder of the 2,976 people listed in the charge sheet,” said the letter, which was signed by Rear Adm. Aaron C. Rugh, the chief prosecutor for military commissions, and three lawyers on his team.

The letter said the men could submit their pleas in open court as early as next week.