Judge rules Afghan militant has been held in Guantánamo illegally, in what lawyers say is the first such ruling in 10 years

A federal judge has found that a former Afghan militant has been held unlawfully at the Guantánamo Bay detention camp, the first time in 10 years that a detainee has won such a case against the U.S. government, his lawyers said.

U.S. District Judge Amit P. Mehta in Washington this week entered a final order and two classified opinions in the case of Asadullah Haroon Gul. One opinion granted Gul’s petition for a writ of habeas corpus after finding he was not part of al-Qaeda, but another found that the end of hostilities in Afghanistan did not merit his immediate release.

The government could appeal the order, and others previously granted habeas have sometimes languished for years. But the decision marks a significant legal turn involving the prison that remains a global symbol of U.S. excesses of power after the Sept. 11, 2001, terrorist attacks on New York City and the Pentagon. The facility became infamous for its detention of some prisoners who had been subjected to brutal mistreatment, including waterboarding and secret interrogations, but who had not been charged. Guantánamo, which has held nearly 800 detainees, now houses 39.