Moazzam Begg speaks to journalists after being released from prison on Oct. 1, 2014 in London, England. (Rob Stothard/Getty Images)

As a prisoner at Guantanamo Bay, Moazzam Begg was able to escape only in his dreams — his nightly chance to leave the grim confines of his U.S. military cell and return to his family in England.

But after being held for seven months this year at a maximum security British prison on terrorism charges that were ultimately dropped, Begg, now free, has seen his dreams turn to nightmares. He’s been imprisoned for nearly four years on three continents by the West’s two leading powers, all without a trial.

(Related: Former Gitmo detainee Moazzam Begg, in his own words)

Amid a new wave of terrorism-related anxiety sweeping Europe as fighters return from Syria, he fears it’s only a matter of time before he’s arrested again.

“How many prisons? How many police stations? How many secret detention sites are they going to put me in, and then not try me? And then not give me my day in court?” said Begg, his face scarred by the beatings he says he endured while in U.S. custody.

Begg, soft-spoken and small in stature, has long been a vocal critic of the sort of post-9/11 brutality that was documented this month in chilling detail by the U.S. Senate Intelligence Committee’s report on CIA interrogation practices.

But his most recent detention has become emblematic here of what human rights groups, Muslim leaders, terrorism experts and even some security officials say is an overzealous response to the threat posed by European returnees from Syria.

The threat itself is undeniable: Thousands of Europeans have flocked to Syria to fight the regime of President Bashar al-Assad, and many have linked up with the Islamic State or other extremist groups. Speaking on propaganda videos from the battlefield, European fighters have called on their countrymen to carry out attacks at home. When American and British hostages were decapitated, it was a Brit who wielded the knife.

And yet, critics say, European governments may be exacerbating the problem with a heavy-handed response that includes mandatory arrests of returnees, lengthy prison sentences and a lack of lighter alternatives, including reintegration programs.

“Arresting and prosecuting people doesn’t really tackle the root causes of the problem,” said Imran Awan, a criminologist at Birmingham City University who studies counterterrorism strategies. “You just alienate and isolate people even more if the government is locking people up and throwing away the key.”

Tightening laws

Policies are expected to get tougher in the months ahead, as several governments push legislation authorizing new powers to seize passports. In Britain, the government has fast-tracked a bill that could prevent former fighters from returning home for up to two years, temporarily stripping them of their rights as British citizens.

Experts say the policies fail to distinguish between hardened extremists who pose a legitimate threat to the West and those who travel to Syria for other reasons, including humanitarian concerns and an interest in toppling a Western enemy: Assad.

Begg, for instance, was arrested in February on charges stemming from his travels to Syria in 2012 and early 2013, before the Islamic State even existed in its current form.

In an interview in his native Birmingham, Britain’s second-largest city, Begg said that he never fought, but he acknowledged working with some of the rebels that Britain, the United States and the West were backing in their struggle against the Syrian dictator.

“Up until late August last year, the British government was seeking to bomb the Assad regime with airstrikes,” Begg said. “But then the policy changed.”

Nearly a year after his return from Syria, Begg was arrested and charged with attending a terrorist training camp. The case against him collapsed in October after Britain’s main domestic intelligence service, MI5, acknowledged to prosecutors that Begg had told them of his plans before he traveled.

Begg has made no secret of his hard-line Islamist sympathies, having operated a bookstore that was a hub for British jihadists in the 1990s and moving his family to Afghanistan in the summer of 2001 to live under the Taliban.

But the 46-year-old has denied participating in violence or being affiliated with terrorist organizations.

Both before and after this year’s arrest, he has been sharply critical of the Islamic State, expressing disgust at the group’s ritualized executions and disregard for civilian life. He even wrote a personal letter from prison to the group’s leader, Abu Bakr al-Baghdadi, urging him to release British aid worker Alan Henning. It remains unclear whether authorities delivered the letter; Henning was subsequently beheaded.

Begg’s lengthy detention this year has only confirmed the suspicions of many Muslims in Birmingham, and across Britain, that their community is being unfairly targeted.

“They feel like they’ve been vilified, demonized and stigmatized,” Awan said. “Moazzam Begg epitomizes the struggle.”

On murky ground

His case is not the only one that has raised hackles.

Two 22-year-olds from Birmingham were sentenced by a judge to 12 years in prison this month after returning from the Syrian front lines. The judge, Michael Topolski, described the pair as “deeply committed to violent extremism.”

But the men’s families said that they felt betrayed by the stiff sentences and that they had been promised leniency in exchange for cooperation.

“This sends out the wrong message to other families who might have concerns about their sons and daughters, and now might not come forward,” the family of one of the men, Mohammed ­Nahin Ahmed, said in a statement.

The security crackdown has extended even to those who never traveled to Syria. On Thursday, a 35-year-old mother of six, Runa Khan, was sentenced to five years in prison for posting statements and photos on Facebook. Khan’s posts included images of a suicide vest and expressions of hope that her young son would one day become a fighter.

Security officials acknowledge that they are on murky ground when it comes to prosecuting Brits for alleged crimes committed in Syria, a country where Western governments have little visibility into events on the ground. Some officials have also called for a more robust debate over where to draw the line in prosecuting extremist language.

Peter Fahy, police chief in the northern English city of Manchester and a leader of the national counterterrorism strategy, recently told the Guardian newspaper that without such a conversation, he feared a “drift toward a police state” in which officers become “thought police.”

Ironically, by locking up people like Begg, the government is actually silencing those who could best rebut Islamic State propaganda, said Ben Ward, Human Rights Watch’s deputy director for Europe.

“It removes the voice of people who might actually be most persuasive in directing young people away from violence,” Ward said.

In Begg’s case, that voice is made more credible by the three years he spent in U.S. custody, during which he says U.S. troops beat him, kicked him, deprived him of sleep, held guns to his head and threatened his then-6-year-old daughter.

Nonetheless, he befriended his guards at Guantanamo Bay and has even traveled with them to speak out against the dehumanizing impact of torture.

“I used to tell the fighters in Syria, when they would ask, ‘What are the Americans like?’ I’d say, ‘Well, some of the guards and soldiers are my friends,’ ” he said. “They were shocked.”

But Begg was not surprised by the abuses he read about this month in the Senate’s report on CIA detention and interrogation.

“Every torture technique that they described, we’ve been talking about till we were blue in the face,” said Begg, who has resumed his work as outreach director for the London-based prisoners’ rights group Cage. “The only thing that surprised me was that they released it.”

Karla Adam in London contributed to this report.