John Walker Lindh, a California native who became known as the "American Taliban" after he was captured alongside Taliban militants in Afghanistan in 2001 will be released from an Indiana prison Thursday. Lindh, now 38 years old, has served 17 years of his 20-year sentence for providing support to the Taliban, will be subject to stringent extra restrictions for three years as provisions of his release.

The pending release has drawn concern from some lawmakers, including U.S. Senators Richard Shelby, R- Alabama, and Margaret Hassan, D-New Hampshire, who in a letter to the U.S. Bureau of Prisons asked for more information about steps the government is taking to ensure public safety.

"I'm very concerned about the release because this is somebody who is a traitor, who copped a plea," Shelby said Wednesday. "I think he shouldn't be let out. I know that's up to the bureau of prisons and everything but I think that'd be a mistake."

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Michael Jensen, a terrorism researcher at the University of Maryland's National Consortium for the Study of Terrorism and Responses to Terrorism, told the Associated Press the special release restrictions for Lindh — which include barring access to the internet without specific permission — imply the government has concerns.

"For three years he's going to be watched like a hawk," Jensen said.

Lindh, his parents, lawyers and prosecutors declined to say to The New York Times where Lindh will live or his plans after prison. But an April court filing in U.S. District Court for the Eastern District of Virginia, Judge T.S. Ellis III outlined the additional post-release conditions he said were requested by a probation officer "given the rare nature of the defendant's crime and his unique personal history and characteristics." They include:

Lindh is prohibited from having any internet-capable device without permission from the probation office. If he obtains permission, the device would be continuously monitored.

Lindh can't have any online communications in any language other than English unless approved.

Lindh can't access or view material that reflects extremist or terroristic views, or communicate with any known extremist.

Lindh can't have a passport issued by any country or leave the U.S. without permission from the court.

Lindh is required to undergo mental health counseling.

The filing says Lindh initially opposed the additional special restrictions, but later agreed to them in writing.

A 2002 police photo of "American Taliban" John Walker Lindh, left, and at right a photo of him from the records of the Arabia Hassani Kalan Surani Bannu madrassa (religious school) in Pakistan's northwestern city of Bannu. Tariq Mahmood / AFP/Getty Images

Lindh grew up in northern California's Marin County, converted to Islam in 1997 as a teenager after seeing the film "Malcolm X," and traveled to Yemen in 2000 to study Arabic and Islam. His mother, Marilyn Walker, told news outlets in 2001 her son then went to Pakistan with an Islamic humanitarian group to help the poor, according to an Associated Press report from that year.

But according to the Justice Department, Lindh crossed from Pakistan into Afghanistan in May or June of 2001 in order to take up arms with the Taliban. He reported to a Taliban recruiting center in Kabul, said he was an American and that he "wanted to go to the front lines to fight," according to a Justice Department statement. He received combat and explosives training at the al-Farooq training camp west of Kandahar, which was associated with Osama bin Laden. An FBI criminal complaint says bin Laden visited the training camp several times while Lindh was there, addressed trainees and at one point met with Lindh in a small group.

Lindh was fighting with Taliban forces in northeastern Afghanistan against the Northern Alliance when al-Qaeda terrorists attacked the U.S. on Sept. 11, 2001.

Lindh and other fighters surrendered to Northern Alliances forces during the U.S. invasion of Afghanistan in late 2001, and he was inside a 19th-century fortress in the northern city of Mazar-i-Sharif during a bloody uprising by prisoners that killed Johnny Michael Spann, a 32-year-old CIA officer. Spann had interrogated Lindh, then 20, and other Taliban prisoners, shortly before the days-long uprising, and Lindh was found with other detainees in the basement of the compound, according to the FBI criminal complaint.

A photo of a gaunt Lindh after his capture prompted shock in the U.S.

This image from television footage taken in Mazar-i-Sharif, Afghanistan, Dec.1, 2001, shows John Walker Lindh, at right, an American who was among survivors of the fortress prison revolt. The man at left was not identified. AP Photo/APTN

Lindh was brought to the U.S. and charged with crimes that could have brought a life sentence. But prosecutors couldn't find evidence that Lindh participated in the deadly riot, according to a 2002 New York Times report, and eventually dropped charges that attempted to link him to Spann's death. In a plea deal, Lindh admitted fighting for the Taliban and was sentenced to 20 years in prison.

At his sentencing, according to the AP, Lindh said he wouldn't have joined the Taliban had he fully understood what they were about and issued an essay condemning violence in the name of Islam. But a National Counterterrorism Center document obtained by Foreign Policy magazine and published in 2017 said Lindh as of May 2016 "continued to advocate for global jihad and to write and translate violent extremist texts."

Johnny Spann, the CIA officer's father, has also opposed Lindh's release. In a letter filed in federal court Monday, he requested in investigation of Lindh's activities, saying the leaked National Counterterrorism Center documents indicate Lindh may have violated the terms of his plea agreement.

"We've got a traitor that was given 20 years and I can't do anything about it," Spann told the New York Times. "He was given a 20-year sentence when it should've been life in prison."