9/11 alleged mastermind Khalid Sheikh Mohammed and 2 others reach plea deal

Three of the five 9/11 defendants at Guantanamo Bay -- including alleged mastermind Khalid Sheikh Mohammed -- have reached a plea agreement with prosecutors, the Department of Defense announced Wednesday.

Gary B. Sowards, the lead attorney Mohammed, confirmed to ABC News on Wednesday evening that the agreement does not include the death penalty but means his client will essentially serve life in prison.

The trial of the five 9/11 conspirators had been stuck in legal delays for almost a decade. No details about the specific terms and conditions of the pre-trial agreement were made public by the DOD. The other two conspirators who have agreed to the agreement aside from Mohammed are Walid Muhammad Salih Mubarak Bin Attash and Mustafa Ahmed Adam al Hawsawi.

The families of 9/11 victims were the first to be notified of the plea deal earlier on Wednesday in a letter from Rear Admiral Aaron Rugh, the chief prosecutor in the case.

A copy of the letter, obtained by ABC News, said that in exchange for taking the death penalty off the table, the three will plead guilty to all charges, including the murder of 2,976 people. They will be sentenced by a panel of military officers.

They also agreed to respond to questions from the verified 9/11 family members "regarding their roles and reasons for conducting" the attacks. The defendants will submit their responses within 90 days.

Patrick White, cousin of Louis Nacke II who was a passenger on United 93 -- the flight where passengers attempted to retake the plane from hijackers, and in the struggle, the aircraft crashed in a field in Pennsylvania -- told ABC News, "I've made my peace with it."

He added that he believes "life in prison along with an admission of guilt that they were complicit in [the] murder of loved ones" was what he was hoping would result from the plea talks.

A White House National Security Council spokesperson told ABC News that the White House learned that the Convening Authority for Military Commissions entered into pretrial agreements with Mohammed and the other two 9/11 defendants on Wednesday.

The spokesperson also said that the president and White House played no role in the process.

Two other 9/11 defendants did not participate in the trial agreement, though only one of them, Ammar al Baluchi, could actually face trial proceedings at Guantanamo.

Last September a military judge ruled that the Ramzi bin al Shibh, the other defendant not participating in the plea agreement, was mentally incompetent to stand trial.

In a statement about the plea agreement, Brett Eagleson, president of 9/11 Justice, said, "We are deeply troubled by these plea deals."

He added that the group acknowledged the decision to avoid the death penalty but wants more access "to these individuals for information."

"These plea deals should not perpetuate a system of closed-door agreements, where crucial information is hidden without giving the families of the victims the chance to learn the full truth," he said.

The ACLU issued a statement saying the DOD's decision was the "right call."

"The government's decision to settle for life imprisonment instead of seeking the death penalty in the case of Khalid Shaikh Mohammed is the right call," Anthony D. Romero, executive director of the ACLU, said in a statement. "It's also the only practical solution after nearly two decades of litigation. For too long, the U.S. has repeatedly defended its use of torture and unconstitutional military tribunals at Guantánamo Bay. The military commissions were doomed from the start and the government’s torture of these defendants makes this plea both necessary and just. Finally, closing the chapter on these cases with a plea agreement will also provide a measure of transparency and justice for 9/11 family members."

Last September, ABC News reported that President Joe Biden rejected a set of demands to form a basis for plea negotiations offered by the five defendants.

Biden agreed with U.S. Secretary of Defense Lloyd Austin's recommendation not to accept their demands, known as "joint policy principles," that they wanted prior to entering into plea agreement talks with prosecutors. According to the New York Times, those demands included avoiding solitary confinement and receiving health treatment for injuries the detainees claim were a result of CIA interrogation methods when they were in the CIA’s "black prisons."

"The 9/11 attacks were the single worst assault on the United States since Pearl Harbor," a National Security Council spokesperson told ABC News in a statement in September 2023. "The President does not believe that accepting the joint policy principles as a basis for a pre-trial agreement would be appropriate in these circumstances. The Administration is committed to ensuring that the military commissions process is fair and delivers justice to the victims, survivors, families, and those accused of crimes."

The five detainees were transferred to the U.S. detention center in Guantanamo Bay, Cuba, in 2006. Their case has been held up by legal proceedings for years, with no trial date set.

On the morning of Sept. 11, 2001, two hijacked passenger jets flew into the Twin Towers of the World Trade Center in New York City, marking the start of a series of coordinated attacks that day against the United States by the Afghanistan-based terrorist group al-Qaida. Nearly 3,000 people were killed that day and thousands more were injured.

-ABC News' Michelle Stoddart contributed to this report.