Infamous “American Taliban” John Philip Walker Lindh, who abandoned his California home to fight with Osama bin Laden and the Taliban, will be sprung from a federal prison this Thursday.

Lindh, 38, will walk out of the Indiana slammer after serving most of a 20-year sentence — with some time shaved off for good behavior, according to the Mercury News of San Jose, California.

And that has loved ones of those killed on 9/11 or in the subsequent war in Afghanistan, where Lindh was captured in December 2001, asking questions.

“I guess the question we have to ask is, does he represent a threat?” Alice Hoagland of Los Gatos, whose son died in the 9/11 attacks, told the paper.

Lindh denounced terrorism when he was sentenced as against Islamic teaching, but has made no public comment since then.

Lindh will be under supervision for three years following his release, and can’t communicate online in any language other than English.

He also can’t communicate with known extremists or view extremist or terrorist material, and can’t leave the country without permission.

And he must also undergo mental health counseling.

Hoagland’s son, Mark Bingham, died when United Airlines Flight 93 crashed into a Pennsylvania field while he and others were fighting al Qaeda hijackers who planned to smash the plane into the White House or US Capitol.

“There are so many more people who have more blood on their hands,” Hoagland said, referring to bin Laden associate Khalid Sheikh Mohammed, who is facing charges from a military commission at Cuba’s Guantanamo Bay of plotting the 9/11 attacks.

Lindh’s divorced parents and lawyers have described him as a devout, idealistic man who wanted to help the Taliban fight their Afghan enemies, not kill Americans.

But others oppose his release.

The family of Johnny Michael Spann, a CIA officer who was America’s first Afghanistan war combat casualty when he was killed in November 2001 in a prisoner uprising after he questioned Lindh, called him a traitor.

“John Walker Lindh had the opportunity to tell Mike right there, ‘You’re an American, I’m an American. … We’ve got weapons in this building and we’re going to overtake this fort,’ ” Spann’s mother, Gail Spann, said in March.

“He chose not to because he was a Taliban. He’s a traitor to our country,” she said.

Lindh was among the Taliban fighters who surrendered after the revolt that killed Spann.

Video later surfaced showing Spann questioning Lindh, who refused to respond, shortly before Spann was killed, the paper reported.

Raised Catholic, Lindh converted to Islam at age 16, inspired by black Muslim leader Malcolm X, and went to Yemen a year later to study Arabic and the Quran.

After a few months at home, Lindh returned to Yemen in 2000 and then traveled to Pakistan to study at an Islamic religious school, where he turned sympathetic to the Taliban’s cause.

After his capture, a federal grand jury indicted Lindh on 10 counts, including conspiring to kill Americans and providing support to al Qaeda and the Taliban.

He faced multiple life sentences, but in July 2002, prosecutors cut a deal with Lindh and his lawyers under which he would plead guilty to supplying services to the Taliban and to carrying an explosive device — a rifle and grenades.

Lindh had also briefly met bin Laden, who visited his Taliban training camp three times.