Showtime is reportedly preparing a documentary on John Walker Lindh, the American convicted in 2002 of joining the Taliban to fight against the United States.

Lindh was sentenced to 20 years in prison for providing material support to the Islamist Taliban in the early 2000s but has now been released three years early reportedly for good behavior.

The documentary is currently entitled Detainee 001 and has been on the drawing board since 2017, Showtime said according to The Wrap.

The documentary reportedly “gives the definitive account of Lindh’s story with never-before-revealed details from his legal case and unpacks challenging truths and shifting allegiances behind one of the most compelling and unresolved mysteries of the post-9/11 age.”

Showtime added, “Lindh’s case set a precedent for how Americans caught up in the War on Terror were prosecuted, and the film examines how American military and justice systems have grappled with the two decades since his detention.”

Vinnie Malhotra, executive vice president of non-fiction programming, Showtime Networks Inc., insisted that Lindh’s case is “central to the most controversial legal issues in the post 9/11 era.”

“Beyond the confusion of a young man from California caught standing side by side with the Taliban, the handling of Lindh’s case remains one of the more curious events since the attacks on 9/11,” Malhotra continued. “Detainee 001 will be particularly important in advancing the discussion of fundamental assumptions about politics, ideology, terrorism, and justice in America.”

Passion Pictures is producing the documentary for Showtime.

Lindh was the first American citizen captured by U.S. forces and charged with fleeing the U.S. to fight on the front lines for Islamic terrorists in Afghanistan.

The “American Taliban” was captured on the battlefield by Northern Alliance soldiers in 2001. U.S. prosecutors connected him to the death of CIA agent Johnny “Mike” Spann during an uprising at Qala-i-Jangi in Afghanistan.

Lindh later pleaded guilty to providing support to the Taliban and carrying a rifle and grenade in aide to Islamist war efforts. According to reports, Lindh has remained radicalized and has not renounced his Islamist beliefs during his 17 years in prison.

Follow Warner Todd Huston on Twitter @warnerthuston.