The man stands furtively on a street corner, his face masked by a hoodie, his tense eyes scanning the crowd for any hint of Islamic State militants.

He was one of them before he left Syria a year ago, and he is afraid.

Now he chain-smokes as he describes the indiscriminate killing, the abuse of female recruits, the discomfort of a life where meals were little more than bread and cheese or oil. He recounts the knife held to his throat by fellow fighters who demanded he recite a particular Quranic verse on Islamic warfare to prove himself.

"It was totally different from what they said jihad would be like," said the man, Ghaith, who asked to be identified by his first name only for fear of being killed. Ghaith eventually surrendered to Syrian soldiers.

While foreigners from across the world have joined the Islamic State militant group, some find day-to-day life in Iraq or Syria much more austere and violent than they had expected.

These disillusioned new recruits also soon discover that it is a lot harder to leave than to join. The Syrian Observatory for Human Rights says the Islamic State group has killed 120 of its own members in the past six months, most of them foreign fighters hoping to return home.

Even if they manage to escape, former fighters are considered terrorists and security risks in their own countries.

Youssef Akkari used to spend hours in his room in Tunisia listening to religious chants and reading, according to his brother, Mehdi Akkari.

One day the family received a message that he was going to Syria. But he lost his glasses and couldn't fight, his brother said, so he was put in charge of preaching jihad to new recruits instead.

After seven months he began to plot his escape, along with two brothers.

The brothers were discovered and killed. Youssef turned himself in to Kurdish fighters and made his way back to Tunisia, where he felt trapped between police harassment and his terror of the vengeful militants. He returned to Syria and died in an airstrike in October.

The Islamic State group works to prevent recruits from leaving from the time they join.

The first step is removing their passports and identity documents. Hamad Abdul-Rahman, an 18-year-old Saudi, said he was met at the Syrian border last summer by militants who escorted him to a training camp in Tabaqa, Syria.

"They took all my documents and asked me if I want to be a fighter or a suicide bomber," Abdul-Rahman told AP from prison in Baghdad, where he was shackled, handcuffed and hooded.

He chose to fight.

There were a lot of foreigners in his camp, he said. The days included prayers, lessons in Sharia, or Islamic law, sports and combat training.

In early September, he surrendered to Iraqi forces. An Iraqi defense ministry video shows Abdel-Rahman minutes after his arrest, identifying himself to soldiers.

Returnees' fate

The predicament for governments is to figure out whether a recruit is returning home to escape from the Islamic State group or to spread its violence.

France has detained 154 returnees and says about 3,000 need surveillance. Britain has arrested 165 returnees. There is no way to prove their intentions.

In Tunisia, where close surveillance of 400 returnees is far more common than arrests, Ghaith is now a free man by most measures. But he does not act like one. His neck still bears a scar where his fellow fighters held the knife.

"It's not a revolution or jihad," he said. "It's a slaughter."