Two days after the revelation of a settlement that reportedly would have removed the death sentence from consideration, US Defense Secretary Lloyd Austin on Friday abandoned a plea deal with alleged 9/11 mastermind Khalid Sheikh Mohammed.

Agreements made with Mohammed and two other suspects on Wednesday seemed to have brought their protracted cases closer to a close, but they also provoked condemnation from prominent Republicans and resentment from some of the families of those slain on September 11, 2001.

In a memo to Susan Escallier, who oversaw the case, Austin said, "I have determined that, in light of the significance of the decision to enter into pre-trial agreements with the accused... responsibility for such a decision should rest with me," adding, "I hereby withdraw from the three pre-trial agreements that you signed on July 31, 2024 in the above-referenced case."

While the accused were being held at the Guantanamo Bay military camp in Cuba, the charges against the 9/11 suspects were mired in pre-trial proceedings for years.

This Thursday, The New York Times revealed that Mohammed, Walid bin Attash, and Mustafa al-Hawsawi had decided to accept a life sentence by pleading guilty to conspiracy rather than stand trial and risk execution.

Whether the men could be judged properly after being subjected to systematic torture by the CIA in the years following 9/11 has been a major point of contention in the legal jousting around their cases.

The plea deals provoked harsh criticism from President Joe Biden's political opponents, although they would have averted that difficult situation.

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House Armed Services Committee Chairman Mike Rogers, a Republican, wrote Austin a letter describing the accords as "unconscionable", while House Speaker Mike Johnson called them a "slap in the face" to the families of the almost 3,000 people who lost their lives in the September 11 attacks.

Republican presidential candidate Donald Trump's running mate, JD Vance, labeled the plea deal as a "sweetheart deal with 9/11 terrorists," saying, "We need a president who kills terrorists, not negotiates with them" during a campaign rally.

Before being captured in Pakistan in March 2003, Mohammed was considered one of Osama bin Laden's most intelligent and trusted lieutenants inside al-Qaeda. After that, he spent three years in covert CIA detention facilities until he was transferred to Guantanamo in 2006.

The skilled engineer was allegedly involved in several significant conspiracies against the United States, where he had studied at university, and has claimed to have planned the 9/11 attacks "from A to Z."

According to US interrogators, Bin Attash, a Saudi national of Yemeni descent, trained two of the hijackers involved in the September 11 attacks. He also admitted to purchasing explosives and enlisting people to join the group that attacked the USS Cole, killing 17 sailors.

He sought safety in Pakistan following the US invasion of Afghanistan in 2001. He was captured there in 2003. After that, he was detained in a network of covert CIA jails.

It is alleged that Hawsawi oversaw the financing of the 9/11 attacks. 

To prevent the defendants from claiming rights under US law, the US utilized the remote naval port of Guantanamo to detain militants caught during the "War on Terror" that followed the September 11 attacks.

Mohammed is known to be the only prisoner to have been subjected to waterboarding 183 times - in US history.

It is defined as torture by international law, and the United States has denounced its application to prisoners of war.

However, the CIA was given permission to waterboard detainees in its covert foreign network by attorneys working for the George W. Bush administration. After that, President Barack Obama ruled it unlawful.

Officially, the CIA has acknowledged that it was used on three detainees before their September 2006 transfer to Guantanamo.