An appeals court allows the government to exit a deal that would have spared the 9/11 mastermind the death penalty.

A divided federal appeals court on Friday threw out an agreement that would have allowed accused Sept. 11 mastermind Khalid Sheikh Mohammed to plead guilty in a deal that would have spared him the risk of execution for al-Qaida’s 2001 attacks.

WASHINGTON—A federal appeals court on Friday quashed plea bargains that would spare three alleged Sept. 11, 2001, conspirators from the death penalty in exchange for confessing guilt, extending the troubled prosecution of Khalid Sheikh Mohammed and other Guantanamo detainees accused of engineering the deadliest terrorist attack in American history.