WASHINGTON—Pentagon prosecutors have made a renewed effort to charge three prisoners at the Guantánamo Bay wartime prison with conspiring in two deadly terrorist bombings in Indonesia in 2002 and 2003.
The prosecutors have tried unsuccessfully twice before to move the case ahead, but the office overseeing military commissions never signed off on the charges. If the charges are approved this time, it would be the first new case to head toward trial at Guantánamo Bay, Cuba, since 2014.
The prosecutors are seeking to charge the prisoners—an Indonesian captive known as Hambali and two Malaysian men—with murder, terrorism and conspiracy in the 2002 nightclub bombings in Bali, which killed 202 people, including seven Americans, and the 2003 Marriott hotel bombing in Jakarta, which killed at least 11 people and wounded at least 80, including three Americans.
The three men have been held at Guantánamo since September 2006. They were captured in Thailand in August 2003 in a joint Thai-United States intelligence raid and spent about three years in the secret C.I.A. prison network.
If convicted, the men could receive a maximum sentence of life in prison because prosecutors chose not to seek the death penalty, said Brig. Gen. John Baker, the chief defense counsel for military commissions, who was notified of the charges on Friday. Each defendant has been assigned a lawyer who is a Marine Corps officer to defend him.
Maj. James Valentine, Mr. Hambali's lawyer, said it would be "a really big stretch" to connect his client to the two attacks. In 2008, three Indonesian men were executed by firing squad for carrying out the Bali bombings, after a 2003 trial at which "the star witness Ali Imron never connected Hambali to these crimes," Major Valentine said. Mr. Imron was the brother of two of the men who were executed, but was spared execution for his role in the bombing because of his testimony.
The charges dated Friday are the latest attempt in three years of efforts to bring Mr. Hambali, Guantánamo's only Indonesian prisoner, to trial. Mr. Hambali's most recent United States intelligence profile described him as "an operational mastermind" of the Southeast Asian extremist group Jemaah Islamiyah and its "main interface" with Al Qaeda "from 2000 until his capture in mid-2003." It also described him as "a mentor" to Guantánamo's other former C.I.A. black site prisoners.
In November 2016, the chief war crimes prosecutor, Brig. Gen. Mark Martins, traveled to Malaysia with two special envoys of the Obama administration in a failed effort to get the government there to agree to incarcerate one of Mr. Hambali's apparent accomplices, who is known as Zubair, as a war criminal convicted by the United States.
The idea was to get Mr. Zubair, whose name is Mohd Farik Bin Amin, to testify against Mr. Hambali and another Malaysian, Mohammed Nazir Bin Lep, who is often called Lillie, in exchange for an arrangement to serve his military commissions sentence in a Malaysian prison.
The Malaysians balked and military prosecutors brought charges against Mr. Hambali alone in June 2017. But the office overseeing military commissions never cleared that case for trial. Six months later, prosecutors brought new charges against Mr. Hambali and the two Malaysians. That case was also never approved.
The spokesman for the Office of Military Commissions, Ron Flesvig, was unable to say Wednesday why the prosecutor issued new charges. The Pentagon lawyer with the title of convening authority for military commissions, Melinda L. Perritano, can decide which charges, if any, to approve for trial, Mr. Flesvig said.
The latest charge sheet differs from those brought by prosecutors in December 2017 in one critical respect: It includes the crime of conspiracy in addition to charges of murder in violation of the law of war, terrorism and other war crimes. In a long-running series of appeals, the Pentagon's Court of Military Commission Review recently declined to consider whether conspiracy was a lawful war crimes charge, leaving intact the 2008 conspiracy conviction of Guantánamo's lone war crimes convict, Ali Hamza al-Bahlul.
Mr. Bahlul, from Yemen, is serving a life sentence at Guantánamo for making a recruiting video for Al Qaeda and for other activities as Osama bin Laden's media adviser before the Sept. 11, 2001 terrorist attacks. Mr. Bahlul's lawyers are appealing that decision at the United States Court of Appeals for the District of Columbia, but prosecutors appear to have been emboldened enough by the Pentagon panel decision to add the charge of conspiracy to the Indonesian bombings case.
Eight of Guantánamo's 40 prisoners are currently charged with crimes.
In 2012, one of them, Majid Khan, a former C.I.A. black site prisoner, pleaded guilty to delivering $50,000 from Al Qaeda to Jemaah Islamiyah, money that was ultimately used to fund the Marriott bombing in Jakarta, Indonesia. Mr. Khan is scheduled to be sentenced in July.
In a March court filing, his lawyers noted, "Mr. Khan's ongoing cooperation in another matter, including his possible testimony at trial in that matter." They did not specify which trial.