A U.S. military judge has ruled that confessions made by Khalid Sheikh Mohammed, the alleged mastermind behind the September 11, 2001 attacks, to FBI agents are inadmissible and cannot be used as evidence at his trial. The decision was issued on Friday, just days ahead of the 25th anniversary of the attacks that resulted in nearly 3,000 deaths in New York, Washington, D.C., and Pennsylvania.

Lieutenant Colonel Michael Schrama, the presiding judge at the military commission at the U.S. naval base in Guantanamo Bay, Cuba, determined that statements Mohammed made during interrogations in 2007 at Guantanamo were involuntary and therefore should be excluded from the prosecution’s case. Schrama noted that prosecutors failed to prove by a preponderance of the evidence that Mohammed’s statements to FBI agents were given voluntarily. The ruling also highlighted that FBI interrogators did not inform Mohammed of his right to remain silent or to consult with an attorney.

Schrama's ruling further cites an “unbroken continuation of the CIA’s psychological conditioning and severe coercion,” referring to Mohammed’s treatment prior to his transfer to Guantanamo. After his capture in Pakistan in March 2003, Mohammed was held at CIA detention facilities overseas where he endured harsh interrogation techniques—including waterboarding—that have been widely condemned as torture. Prosecutors had previously excluded any statements made by Mohammed while in CIA custody but had sought to admit those made during FBI questioning at Guantanamo.

The decision comes amidst ongoing legal challenges regarding the fair trial prospects for Mohammed and three other defendants accused of planning the 9/11 attacks. Their trial date was set earlier this week for June 5, 2028. The proceedings have faced multiple delays over issues including allegations of torture and the legality of evidence. A proposed plea deal that would have removed the death penalty as an option was withdrawn last year following opposition from some family members of the victims.

Prosecutors retain the option to appeal the judge’s ruling. A spokesperson for the military court did not immediately respond to requests for comment. The question of how to handle evidence obtained under coercion continues to underscore the complexities of trying high-profile terrorism cases within the military commission system.