Prosecutors have issued a new deadline — Sept. 18 — for four detainees at the American military prison at Guantánamo Bay, Cuba, to show their willingness to plead guilty to plotting the attacks of Sept. 11, 2001, and receive a maximum punishment of life in prison.
The fifth defendant in the case has been found incompetent to stand trial and is likely to be removed from the case.
In a series of recent communications, prosecutors in the Sept. 11 case notified the judge that they will not call witnesses to contest a mental health panel’s finding last month that Ramzi bin al-Shibh is not sane enough to stand trial. Without a challenge, the judge is expected to sever him from the case when hearings resume next week after a 22-month hiatus.
Prosecutors also notified defense lawyers that they have until the hearings start next week to submit signed agreements if Khalid Shaikh Mohammed, accused of masterminding the attacks, or any of the other defendants will agree to plead guilty. They describe the deadline as driven by the scheduled Oct. 7 departure of the current overseer of the case, Jeffrey D. Wood. In March 2022, Mr. Wood authorized prosecutors to pursue guilty pleas that would spare the defendants a capital trial to resolve the long-running case.
His replacement, retired Brig. Gen. Susan K. Escallier, has been appointed to succeed him on Oct. 8. It is not known whether she will authorize prosecutors to continue discussing a plea, or she herself will become the person to entertain proposed plea deals.
Hearings had been on hold while prosecutors awaited a response from the White House on whether it would establish a torture treatment program for the defendants and agree that they would not have to serve their sentences in solitary confinement as part of a plea agreement. President Biden rejected those conditions this month.
Personnel changes and the examination of Mr. bin al-Shibh’s sanity also had forced some delays.
Mr. bin al-Shibh is accused of organizing a cell of hijackers from Hamburg, Germany, and of aspiring to reach the United States to help commandeer an airplane in the attacks that killed nearly 3,000 people in New York and Pennsylvania and at the Pentagon.
He was the first of the five defendants in the case to be captured, on Sept. 11, 2002, in Karachi, Pakistan, and was held longest in the secret C.I.A. prisons that tortured captives to uncover Qaeda secrets.
His sanity has been a subject of concern for years. He was repeatedly ejected from the courtroom because of his outbursts and complaints that the C.I.A. was depriving him of sleep.
In 2014, the Army judge presiding in the case removed him to undergo evaluation. But prosecutors argued to have him reinstated in the joint conspiracy trial.
But this summer a board ordered by the judge diagnosed Mr. bin al-Shibh with post-traumatic stress syndrome and some aspects of psychosis, making him not competent to assist in his own defense or voluntarily plead guilty.
Court filings showed that prosecutors notified the judge last week that they would not be calling experts when the hearings resumed to challenge the diagnosis or discuss what treatment might restore his competency. Mr. bin al-Shibh’s lawyer, David I. Bruck, likewise notified the court that he would not call witnesses to discuss the evaluation. It will then be up to the judge to decide whether to separate him from the case or suspend the proceedings pending treatment.
The prosecutors had hired a forensic psychiatrist, Michael Welner of West Palm Beach, as a consultant and had planned to have him testify on the topic. Dr. Welner testified this year in Guantánamo’s other capital case that a Saudi man voluntarily confessed to his crimes in 2007 after four years in C.I.A. custody, an opinion the military judge in that case rejected.
