Saudi Arabia's maximum security Al-Hair prison gets more attention for its luxury suites devoted to conjugal visits than for its well-documented human rights abuses. But make no mistake, the facility is the Kingdom's version of Guantanamo Bay.

Blindfolded men in handcuffs and leg shackles shuffle through the halls, led by members of the Mabahith — the Saudi secret police. Prisoners live one man to a 6-feet-by-12-feet cell, where they eat, bathe, pray, and spend the majority of their days. Colonel Mohamed Al Asmary, who currently runs Al Hair, told VICE News that there are approximately 1,100 prisoners in the facility, all serving sentences for crimes related to terrorism.

When asked if that tally includes activists who have rubbed the royal family the wrong way, the colonel says "there are no political prisoners here."

Instead, according to Asmary, Al-Hair is home to members of "deviant groups" like al Qaeda and the Islamic State. One of those prisoners was made available earlier this year for an interview with VICE co-founder Suroosh Alvi featured in "Enemies at the Gate," a segment on tonight's episode of VICE on HBO, which airs at 11pm ET.

In a small room deep inside the prison, a stocky man in his early 40s wearing a traditional white thobe (and a decidedly non-traditional black knit cap) sits on a pleather couch, waiting for the interview to begin. Several government minders hover nearby. VICE News is not allowed to reveal the man's identity, so we'll simply call him the sheikh.

"He is Mutawa," or an Islamic advisor, explains Colonel Omar Alzallal Alkahtani of the Ministry of the Interior.

The sheikh, a Saudi national, is well known in Saudi Arabia for his many appearances on television and at mosques throughout the country. But he's no televangelist serving time for embezzling money from his followers. He is here because he joined the Islamic State (IS) in April 2014 when he traveled to Syria to engage in what he calls "relief work."

"I was not in it to battle," he says in slow, soft-spoken Arabic. "I was in it to call people to worship."

According to the sheikh, his role in the Islamic State was to act as a kind of traveling missionary, sticking to the outer edges of IS-controlled territory in hopes of avoiding the bombing being done by American and Syrian jets.

"I would go there, preach to locals, travel and continue preaching at the next area to call people to Allah," he explains. He also defused potentially explosive situations among those who were letting the strain of forming a caliphate get to them.

The sheikh tells his story to VICE co-founder Suroosh Alvi as Colonel Omar Alzallal Alkahtani of the Ministry of the Interior looks on. (Photo via VICE on HBO)

"There was a lot of in-fighting," he says of IS fighters. "So I would mediate between them, and eliminate threatening behavior within the group."

While in Syria, the sheikh met young Saudis who are swelling the ranks of IS; Saudi nationals are believed to be the second-largest contingent making up the group's foreign fighters, behind only Tunisia.

"On the first day that I went to Syria, they held a meeting to meet me," the sheikh tells VICE News. "I am considered one of the sheikhs of Saudi Arabia, and they knew me…. They introduced me to the leadership in Tel Abyad," a city on the Syria-Turkey border. He says the young Saudis were keen to discuss "the situation of Arabic and Islamic countries, as well as their stance on European and infidel nations."

The sheikh explains the root of the problem that the young Saudis who run away from home have with the Kingdom, which this year celebrated the 70th anniversary of its alliance with the United States.

"[It's] based on the Saudi leadership's dealings with infidel nations, their support and friendship," the sheikh says. "They believe that Saudi Arabia has participated in the killing of Muslims. Just like what happened in Yemen and Iraq."

This, under some interpretations of Islam, makes the leaders of Saudi Arabia kuffar, or apostates, who can legally be killed.

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VICE News' 'Escape to the Islamic State'

This year has seen an uptick in actions against the Kingdom claimed by the Islamic State. In January, four members of IS crossed into the country from Iraq and killed two border guards and their commanding officer in an incident that ended only when one of the militants detonated his suicide vest. In April, two policemen were shot in the capital of Riyadh by a gunman who Saudi authorities say was acting on instructions from the Islamic State. Later that month, Saudi authorities said they had foiled a bomb plot targeting the US embassy. In May, 21 people were killed when a suicide bomber attacked a Shia mosque in the eastern city of Qatif. The Islamic State claimed responsibility.

While IS attacks have elicited stern rhetoric from Western politicians and spurred ongoing bombing campaigns against the Islamic State, the group is not on the run, says the sheikh. Instead, its members are focused on the future of the caliphate.

"They are now trying to rebuild the country, its infrastructure," he says. "To build a bedrock in place of the old Syrian government's constituencies. To build an educational system, an Islamic school system, a court system, a military system. Ministry of this, ministry of that. Then, they can work with local people in ways that are different from how they are used to dealing with their former government."

About nine months after he joined IS, the sheikh fled and crossed into Turkey, where he made arrangements to turn himself in at the Saudi embassy in Istanbul. The sheikh claims that he found himself ideologically at odds with members of IS, whose flagrant use of violence he found distasteful.

"All of this killing is the result of the apostasy belief, where killing is allowed," he says. "I disapprove of the spreading of the apostasy belief as well as reckless and unfounded judgments on people. No solid proof is established. Based on these reckless judgments, they commit such acts as beheadings."

The Saudi minders seem pleased with the sheikh's interview performance — which is probably good news for him, as he has yet to receive his sentence. If he is lucky, he will be transferred to the country's rehabilitation program at the Bin Nayaf Counseling and Care Center. There, de-radicalization specialists will attempt to turn him into a model Saudi citizen, one who can speak to audiences of young, angry men about the perils of joining the Islamic State.

He could be a valuable asset. After all, as Alkahtani points out:

"He is very famous!"