He had been in Syria for almost six months, serving in the morality police of the so-called Islamic State, when he decided he’d seen enough.

The recruiters had promised an Islamic utopia but it was just a cruel police state, one he wasn’t willing to die for. He was frightened and disillusioned.

He wanted to go home to Canada.

He left the city of Manbij during the night, taking a motorcycle north to Jarabulus and crossing into southern Turkey, where he was arrested and deported.

“All that’s behind me,” the Pakistani-Canadian, lanky and in his 20s, told Global News in an interview after returning to the Toronto area last summer.

“We all do things that we regret.”

There are said to be dozens like him across Canada, “returnees” who have spent time in terrorist groups and come home. And with ISIS collapsing in Syria and Iraq, more are expected to turn up.

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WATCH: A counsellor talks about the former ISIS recruit now living in the Toronto area

1:02 Former ISIS recruit now living in the Toronto area Former ISIS recruit now living in the Toronto area

They raise obvious security concerns. Are they determined to carry on the fight from Canada — recruiting, fundraising and plotting? Or are they disenchanted and want only to resume ordinary lives?

“In the worst-case scenario, one or more of those returnees with terrorist and/or combat experience may target elements of Canadian society,” said an RCMP report obtained under the Access to Information Act. “They may use Canada as a base for targeting others, including the United States.”

How Canada is dealing with returnees is seldom discussed in public. Few are charged, owing to the challenge of proving what they did abroad. And most seek anonymity for understandable reasons.

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But declassified national security documents and interviews with officials, experts and a self-professed Canadian ISIS returnee, offer a unique glimpse into the secretive world.

LISTEN: What happens when an ISIS member returns to Canada? Global News investigative reporter Stewart Bell reports.

“Any individual, of course, that we know is returning from a conflict that we suspect of being involved with a terrorist organization, we will pay very close attention to,” RCMP assistant commissioner James Malizia said in an interview.

Returnees are “one of our highest priorities,” said Malizia, who is in charge of the RCMP’s national security program. “We’re keeping a close eye on the situation as it unfolds in Syria and Iraq and other conflict zones. Certainly, it’s a concern to us.”

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Royal Canadian Mounted Police assistant commissioner James Malizia speaks at a press conference at RCMP headquarters in Ottawa about the arrest of a Somali man, Ali Omar Ader, for his involvement in the kidnapping of Canadian journalist Amanda Lindhout, Friday, June 12, 2015. THE CANADIAN PRESS/ Patrick Doyle.

One of those returnees now lives in a spacious house with a satellite dish and a two-car garage and attends a university in the Toronto region. Because he fears arrest, he agreed to speak to Global News on the condition he not be identified.

Many of the details of his account could not be verified but Global News has viewed evidence of the RCMP’s interest in him, and those familiar with his story, including an academic expert who has spoken with him, believe he is credible.

After graduating from a Greater Toronto Area high school in 2012, the Canadian said he traveled to Pakistan, the country he left with his parents at age six, and applied to attend university in Lahore.

The mosque he attended was affiliated with the armed Islamist group Lashkar-e-Tayyiba and the discussion often turned to the need to liberate Muslim lands. “They talked mostly about jihad,” he said.

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Among the Lashkar devotees, many of whom had fought in Afghanistan, young men were expected to take up arms in northern Pakistan or Syria. Not wanting to battle the Pakistani military, he chose Syria. “They were sending people,” he said, estimating between 10 and 15 had left.

The recruiter told him what to do, he said. Using his own money, he bought a plane ticket to Istanbul, then made his way to Sanliurfa, a Turkish city near the border, where he met the ISIS facilitators who brought him to Syria.

READ MORE: Feds looking into reports of 2 Canadians among ISIS militants captured in Mosul secret tunnel

It was January 2014 when he arrived in Jarabulus. The first stop was the screening office, where he was asked about his experience and Islamic knowledge, and whether he wanted to be a fighter or suicide bomber.

He was assigned to the ISIS morality police, known as Al-Hisbah, and sent to Manbij, a city in Aleppo district. Former U.S. president Barack Obama’s defense secretary, Ash Carter, has called Manbij a key city for foreign fighters and a base for “external operators” plotting attacks in the West.

ISIS had just taken control of the city from rebel forces when the Canadian arrived. The role of the Hisbah police was to impose the brutal, uncompromising ISIS vision of an Islamic society on the population. Music, shaving, mixing of the sexes, cigarettes, homosexuality, satellite dishes, alcohol and drugs were among the many things banned.

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1:22 Winnipeg mother trying to bring son to Canada after he was freed from ISIS Winnipeg mother trying to bring son to Canada after he was freed from ISIS

Armed with a Glock pistol that he bought himself, the Canadian patrolled the streets ensuring the strict ISIS codes of dress and conduct were obeyed.

Punishments could be severe. Those caught flirting were locked in a cage for a day, he said. Smoking brought a lashing. Thieves had their fingers or hands amputated. Women whose faces were uncovered would be beaten, the United Nations reported in August 2014. Video shows those accused of homosexuality being thrown off rooftops.

The most terrifying sentence was for “apostates,” meaning anyone suspected of disloyalty to ISIS beliefs. They were publicly shot or beheaded and then crucified and left for days as a warning to others.

An ISIS video obtained from the Middle East Media Research Institute shows one such atrocity in Manbij on June 8, 2014. Two men, described as “Allah’s enemies” and “infidels,” are shown kneeling and blindfolded with their hands tied. After they have been shot dead, their bloodied bodies are taken to a wooden scaffolding and tied with their arms outstretched.

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“People would die for their crimes,” the Canadian said. “It is what it is. You can’t sugar coat it.” But while he acknowledged he had witnessed killings, he said he never killed anyone himself. He insisted he was gentle with people. “I’d be too nice,” he said. “I’d be slack.”

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1:53 Former undercover agent on what needs to be done when dealing with returning terrorist fighters Former undercover agent on what needs to be done when dealing with returning terrorist fighters

Those charged with keeping track of Canada’s foreign terrorist fighters work in a room deep in the former RCMP headquarters building, where clocks are set to Istanbul, Philippines and London time. Below them are four giant screens, one showing a CCTV feed from Parliament Hill. The shaggy head of a stuffed bison looks over it all.

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This is the National Security Joint Operations Centre, the Ottawa bunker where officials from Canada’s key security agencies sit side by side, trying to stay on top of the threats posed by violent extremists coming and going from the country.

The centre is the hub of Canada’s fight against what officials call high-risk travellers — those trying to leave the country to join violent extremist groups, as well as those returning following stints as foreign terrorist fighters.

It’s a busy place, declassified documents show: in the four months after the centre opened in October 2014, the Canada Border Services Agency “actioned” almost 800 RCMP requests through the centre, made 500 information disclosures and issued 180 lookouts.

The workstations were mostly empty for our visit in July, but usually, they’re occupied by members of the RCMP, Canadian Security Intelligence Service, CBSA and Immigration, Refugees and Citizenship Canada.

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0:40 Ralph Goodale comments on return of ISIS fighter to Canada Ralph Goodale comments on return of ISIS fighter to Canada

The Communications Security Establishment, Canadian Armed Forces, Global Affairs Canada, Financial Transactions and Reports Analysis Centre and Canadian Air Transport Security Authority send officials as needed.

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The centre was a response to the surging numbers of Canadians leaving for places like Somalia, North Africa and more recently Syria and Iraq — and the sobering realization they could one day come back with terrorist training, combat experience and a global network of contacts.

Known to the security community as the NSJOC, the centre is a “co-operative venture, namely partner agencies utilizing their respective databases and mandates to analyze information and determining the best way forward,” the RCMP director of National Security, Supt. Steve Nordstrom, wrote in a recent paper.

Cases come in from the half-dozen Integrated National Security Enforcement Teams (INSETs) across the country, which are tipped off by local police, community members, and families. It’s not unusual for investigations to begin as missing persons reports.

“Sometimes we receive this information from family or friends that’ll advise us, ‘Hey my son, my daughter looks like they’ve taken their passport, picked up and I believe they’re travelling right now, and they’ve left me a note to say that we’re heading to Syria or Iraq or some other conflict zone to join a terrorist organization,’” Malizia said.

“That information then goes from the INSETs into the NSJOC, and the National Security Joint Operations Centre then at that point allows us to start understanding what that looks like, to see: can we intercede, can we actually intercept these individuals while they’re still in Canada, in transit?”

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The security officials will mine their respective records to get a fuller picture of what they’re dealing with and figure out a response, which could range from soft measures like interventions and passport seizures to arrests and charges.

The centre also has what Malizia called “a direct feed into our international partners.” Notably, the RCMP has been working with the Turkish national police to identify suspected Canadian extremists transiting through Turkey.

Several suspected extremists have been arrested in Turkey and returned to Canada but the RCMP report said there were risks associated with receiving information about returnees from countries with poor human rights records.

“The RCMP should be wary of utilizing information about subject X when it has been provided by a country’s law enforcement forces that are known to use torture, unreasonable detention, or lack of due process,” it said.

Stopping would-be terrorists before they reach a training camp or combat zone is critical, Malizia said. “The advantage for us is we’re able to intercept someone before they receive the combat skills which would, of course, render them a higher risk if they were to return to Canada.”

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1:10 Ralph Goodale on anti-radicalization centres Ralph Goodale on anti-radicalization centres

But a lot of them aren’t stopped. By the end of 2015, about 180 extremists “with a nexus to Canada” were active in terrorist groups around the world, including about 100 in Syria and Iraq, according to the most recent government figures.

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The Canadian said it didn’t take him long to see the rot in the heart of ISIS. For all its angry rhetoric about defending Muslims, ISIS killed a lot of them. He said delegations from rival armed factions would arrive in Manbij for talks, only to be shot dead as they were leaving in their vehicles.

As for ISIS leader Abu Bakr Al-Baghdadi, while he sent his fighters on suicide missions, he went to lengths to safeguard his own personal security. And while it was supposed to oppose nationalism, the Canadian said the Arabs who dominated ISIS looked down on South Asians like him.

“I saw hypocrisy, a lot of hypocrisy,” he said.

A resident of Manbiji said ISIS cut off his hand. MEMRI

Seeing killings affected him, and he got scared. He knew he would one day be sent to the front lines but he didn’t want to die. He had kept in touch with his Canadian family on the internet and wanted to see them again.

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He spent a week planning his escape, he said. Using Google Maps to plot a route, he reached the Turkish border crossing at Jarabulus and was arrested. He said he showed the Turkish authorities his Canadian passport and Ontario driver’s license. But they wouldn’t let him go back to Canada, he said.

“They sympathized with me,” he said. They told him the Canadian authorities would prosecute him so they would deport him to Pakistan instead. “Save yourself,” they told him. The Turkish police drove him to the airport and made sure he got on a flight to Pakistan, he said.

Days after he left, on June 19, 2014, Al-Baghdadi, having captured the Iraqi city of Mosul, declared he had established an Islamic caliphate and that he was its leader. “I was just happy that I was out of there,” the Canadian said.

WATCH: The fight against home-grown terrorism

He remained in Pakistan for two years before moving back to Toronto. As he got off the plane at Pearson airport in the summer of 2016, he went through a passport check without any trouble. He told the immigration officers he’d been in Pakistan. Since he’d used a Pakistani passport to travel to Syria, the officers had no reason to doubt him.

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But then he made a mistake.

In posts on social media, he criticized the ISIS leadership. To underscore his point, he said he was an ex-ISIS member. “It slipped out,” he said. Global News independently obtained a copy of the online posts. Before long, two national security investigators were at his door.

When the RCMP identifies returnees it will “meet with them and get a sense of where they’re at, what their intentions are,” Malizia said. “There are some individuals that return from a conflict zone that may still have motives to now maybe conduct an attack or do something in Canada or in another country.”

“But there are others that come back from a conflict zone and may be seized with post-traumatic stress disorder or disillusioned,” he said. “And some do come back and decide to re-integrate themselves in society and try to live a normal life.”

Malizia said if police suspect they were active in a terrorist group, “we’ll fully investigate and if we can lay criminal charges we will.” In addition, police can monitor the social media activities of returnees, revoke their passports and place them on the no-fly list, according to the RCMP foreign fighter report.

The report also said police “community engagement specialists” should “assist the returnee in engaging with supportive community resources, including those who would help steer the individual away from criminal activities associated with terrorism.”

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The European Commission’s Radicalization Awareness Network said much the same thing in a recent report. “In the long term, authorities and local communities need to work together to resocialize or integrate returnees into society.”

Around the time the Canadian Security Intelligence Service and RCMP came calling, Mubin Shaikh paid him a visit as well. A U.S. journalist had found the returnee’s contact information in data retrieved in Syria and suggested Shaikh speak to him.

Shaikh had once flirted with radicalism himself but had turned against it and infamously served as an undercover agent in the Toronto 18, the Al Qaeda-inspired terrorists who plotted attacks in Ontario until their arrests in June 2006. Shaikh went on to earn a master’s degree in policing, intelligence and counter-terrorism and became active in deradicalization.

Paid RCMP informant Mubin Shaikh gives the thumbs up signal as he speaks outside a courtroom in Brampton, Ont., on Tuesday March 24, 2009, after a judge convicted a member of a home-grown terrorist cell. The judge ruled Shaikh had not entrapped the convicted youth or carried out criminal acts in infiltrating the “Toronto 18.” THE CANADIAN PRESS/Colin Perkel. CP

After meeting the ex-ISIS member, Shaikh began spending time with him, often weekly, trying to “contain his ideology and to point him in the right direction, gently challenging some of his ideas.”

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Shaikh said he was a “middle space” between the youth and the police. The parents help as well, and he has told his imam. “He’s largely self-deradicalized. He’s not completely there,” Shaikh said. “He’s not a public safety threat.”

Returnees can fall into a gap, Shaikh said. Police have a mandate to investigate but are often unable to lay charges. That leaves the community to deal with them. But who is best placed to take on the sensitive task?

“If you decide that they do need some kind of counselling, the people that you send them to, what qualifications do they have? Just because a person is an imam doesn’t qualify them automatically to do this kind of counseling.” Imams and community leaders need training on how to recognize and confront extremists, Shaikh said.

That is beginning to happen. In March, 20 imams from the Toronto area, Hamilton, Ottawa, and Edmonton attended an RCMP counter-terrorism awareness workshop. They learned about the Salafi jihadist mindset, behavioural indicators, counter-terrorism law and Toronto’s radicalization prevention efforts.

“Government cannot do it alone,” said Hamid Slimi, who heads the national security committee of the Canadian Council of Imams, which took part in the training. “Therefore, council of imams said we will work with the authorities, including RCMP, to combat any potential threat or any misguided radicalized kind of thinking.”

AUG. 3, 2007 — Hamid Slimi is photographed at a mosque in Toronoto, Ont. Aug. 3/2007. Slimi is working with Muslim youth.Photo by Kevin Van Paassen/The Globe and MailJULY 27, 2007. CP

He said returnees were a concern. Where will they go when they come back? What if they bring children back with them? What about the ones nobody even knows about? “Who is going to follow up with them? Authorities? Community is not ready for that.”

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The council can play a role but “it doesn’t have a magic wand,” he said. A hotline was to be set up shortly, allowing those with concerns about extremism to speak directly to an imam. Highly qualified people are ready to step up, he said, “but not too many, there is a shortage.”

“We’re still making baby steps.”

The ex-ISIS police officer said returnees must be screened and those who pose a threat should be dealt with. But he doesn’t believe the true believers will ever come back. They will die in Syria, he said.

He insisted Canadians shouldn’t worry about the ones like him who abandoned ISIS. But he said they needed support and guidance. “Don’t keep them isolated,” he said. “You have to have someone to talk to about it.”

He still struggles, he said.

“It’s not like you can become deradicalized right away the next day,” he said. But he said he was focused on his life goals. He has a girlfriend, supportive parents and Shaikh, whom he said “loosened the noose around my neck.”

The RCMP has not charged him, likely because they don’t have enough evidence. “The RCMP’s last message to me was, ‘Stay focused on school,’” he said. The investigating officer told him, “If I come back, I will charge you,” he said.

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He is uncertain about his future, not knowing if he might be arrested one day. But he also knows that if he had stayed in Syria, he would be dead like his former comrades. He said he was done with all that. “I have too much to lose now,” he said.

“I’ve moved on.”

Stewart.Bell@GlobalNews.ca