Despite being held for 14 years without charge at Guantanamo Bay; despite the torture, beatings, and psychological trauma he says he endured there; and despite signs that British intelligence agents knew of the abuse, 48-year-old Shaker Aamer says top UK officials should be granted legal immunity if it will encourage them to tell the truth about their government’s complicity in such atrocities.

“They should be guaranteed that they are not going to go behind bars, so they can tell their part of the story,” Aamer said in an interview with ITV News, his first since returning to the UK in October.

Comparing the U.S. military prison to Harry Potter’s Azkaban—where creatures suck the happiness from criminals—the father of two said Guantánamo Bay is designed to “destroy a human being totally”—mentally, physically, and spiritually.

Aamer called for U.S. President Barack Obama to shut down the offshore prison immediately.

“Everything that happened to us is a war crime in Guantánamo,” he said. “Everything that is happening right now is a war crime in Guantánamo.”

“My message to the President of the United States [Barack] Obama … that if he wants to be the hero, to close Guantánamo,” Aamer continued. “If he really wants to establish justice, if he really wants to live by his word, he’s not going to need to wait for the whole United States of America to support him. He should practice his right as a president, his right as the head of the army, and just close it—close it and the brothers they will help him, if you start thinking about the brothers in Guantánamo as human beings, they will help you to close it.”