A military judge on Wednesday ruled that the plea deals for the alleged mastermind behind the 9/11 terror attacks and two accomplices were valid, reopening the possibility that the men could avoid the death penalty in exchange for life sentences.

Air Force Col. Matthew McCall said in his ruling that Defense Secretary Lloyd Austin did not have the authority to void the agreements on Aug. 2, just days after the Pentagon said the plea deals were entered, a spokesperson for the Office of Military Commissions confirmed to USA TODAY.

Khalid Sheikh Mohammed and two of his top lieutenants, Walid bin Attash and Mustafa al-Hawsawi, agreed to plead guilty to the murder of 2,976 people and other charges in exchange for taking the death penalty off the table. Mohammed is described as the “principal architect of the 9/11 attacks” in the 2004 report by the 9/11 Commission.

The deals, which marked a significant step in the case against the men accused of carrying out one of the deadliest attacks in U.S. history, were met by swift pushback. Days after the agreements were announced, Austin voided them.

"I have determined that, in light of the significance of the decision to enter into pre-trial agreements with the accused in the above-referenced case, responsibility for such a decision should rest with me," Austin wrote in a memo to Brig. Gen. Susan K. Escallier, a retired Army general who authorized the deals and whom Austin had appointed to oversee military commissions.

In Wednesday's ruling, McCall said Austin's decision to rescind the deals in August came too late, according to the New York Times, which first reported the ruling. He also rejected the premise that Austin has such sweeping authority over the case.

“The Prosecution did not cite, and the Commission did not find, any source of law authorizing the Secretary of Defense to ‘withdraw’ Ms. Escallier’s authority to enter into a PTA (pretrial agreement),” the ruling said, according to the legal news site Lawdragon.

Pentagon spokesperson Maj. Gen. Pat Ryder said in a statement that the Pentagon is reviewing the decision and "don’t have anything further at this time.” It's unclear if the government will appeal the ruling.

Families of 9/11 victims are not in agreement on the plea deals, with some backing them and others set on the case going to trial and the men facing the possibility of death.

In a letter about the plea agreements from the U.S. Department of Defense to the families, the agency said the deals would allow loved ones to speak about the impact the attacks had on them at a sentencing hearing next year. The families would also have the opportunity to ask the al-Qaeda operatives questions about their role in the attacks and their motives for carrying it out.

All three men have been in U.S. custody since 2003, spending time at Guantanamo and prisons overseas. In CIA custody, interrogators subjected Mohammed to “enhanced interrogation techniques” including waterboarding him 183 times, according to the Senate Intelligence Committee's 2014 report on the agency’s detention and interrogation programs.

Contributing: Minnah Arshad, Michael Loria, Tom Vanden Brook and Josh Meyer, and Reuters