(MCCLATCHY) The FBI agent who first interrogated Abu Zubaydah — the war-on-terror captive who became the guinea pig in the CIA’s post- 9/11 interrogation program — said Wednesday that the case of the captive represents “the A to Z of where we went wrong as a nation.”

The Palestinian prisoner whose real name is Zayn al Abdeen Mohammed al Hussein, 45, is due at the war court Thursday afternoon to testify in the Sept. 11 case about a very narrow topic: Whether he can vouch for claims by an accused 9/11 plotter, Ramzi bin al Shibh, that somebody’s causing noises and vibrations in Guantánamo’s most clandestine prison, Camp 7. The two men are held there with 12 other former CIA “Black Site” captives.

“His case represents the A to Z of where we went wrong as a nation,” said former FBI agent Ali Soufan, who interrogated some of the most prized captives of the war on terror, and considered Abu Zubaydah “a high-ranking terrorist” at his capture. “In a way, it was the original sin that led to the institutionalization of the so-called Enhanced Interrogation Techniques.”

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