John Lindh, a U.S. volunteer for the Taliban, released from prison

John Walker Lindh, the American captured in Afghanistan in 2001 fighting for the Taliban, was freed early from federal prison on Thursday after serving 17 years, the Federal Bureau of Prisons said.

Lindh, who was 20 years old when he was captured, was released amid concerns about his rehabilitation.

Lindh, now 38, left the prison in Terre Haute, Ind., Thursday morning. He had been sentenced to 20 years after pleading guilty in 2002 to charges of supplying services to the Taliban and carrying an explosive during the commission of a felony.

Now 38, Lindh is among dozens of prisoners set to be released over the next few years after being captured in Iraq and Afghanistan by U.S. forces and convicted of terrorism-related crimes following the attacks by al-Qaeda on Sept. 11, 2001.

His release has brought forth objections from officials who asked why Lindh was being freed early and what training parole officers had to spot radicalization and recidivism among former jihadists.

U.S. Secretary of State Mike Pompeo called Lindh's release "unexplainable and unconscionable."

"There's something deeply troubling and wrong about it," he said on Fox News on Thursday morning.

His release is also opposed by the family of Johnny Spann. The CIA officer was killed in Afghanistan during an uprising of Taliban prisoners. Spann had interrogated Lindh shortly before the attack.

Leaked U.S. government documents published by Foreign Policy magazine show the federal government as recently as 2016 described Lindh as holding "extremist views."

"What is the current interagency policy, strategy, and process for ensuring that terrorist/extremist offenders successfully reintegrate into society?" asked Richard Shelby and Margaret Hassan, U.S. senators from opposite sides of the aisle, in a letter to the Federal Bureau of Prisons.

Lindh's parents, Marilyn Walker and Frank Lindh, did not respond to requests for comment. 

Internet usage to be monitored

Melissa Kimberley, a spokesperson for the prison in Terre Haute, could not confirm details of Lindh's release other than it would be on Thursday.

U.S.-born Lindh converted from Catholicism to Islam as a teenager. At his 2002 sentencing, he said he travelled to Yemen to learn Arabic and then to Pakistan to study Islam.

He said he volunteered as a soldier with the Taliban, the radical Sunni Muslim group that ruled most of Afghanistan from 1996 to 2001, to help fellow Muslims in their struggle or "jihad." He said he had no intention "to fight against America" and never understood jihad to mean anti-Americanism.

Lindh told the court he condemned "terrorism on every level," and attacks by al-Qaeda leader Osama bin Laden were "completely against Islam."

But a January 2017 report by the U.S. government's National Counterterrorism Center that was published by Foreign Policy said that as of May 2016, Lindh "continued to advocate for global jihad and to write and translate violent extremist texts."

NBC News reported Lindh wrote a letter to its Los Angeles station KNBC in 2015 expressing support for the Islamic State in Iraq and Syria (ISIS), saying the militant group was fulfilling "a religious obligation to establish a caliphate through armed struggle."

It has been reported that Lindh will live in eastern Virginia upon release.

A judge recently imposed additional restrictions on Lindh's post-release supervision, including monitoring of his internet use.