LONDON -- Two years ago, a young man who now calls himself Abu Muhajir slipped into Syria with a few friends and $80,000, forsaking what he said was a job as a high school science teacher in North America to wage jihad.
In a conversation by text message in recent weeks, he said he was raised in a religious family, studied at a madrasa on Sundays and had no non-Muslim friends growing up. And he suggested that Western governments could indeed have cause for worry that foreign jihadis in Syria might return home to carry out attacks.
"Attacks occurring on the soil of Middle Eastern countries," he said. "We can only expect a response. Americans are still in Afghanistan."
More than 70 Americans are thought by intelligence and counterterrorism officials to have traveled to Syria to fight President Bashar Assad's government. One of them, still publicly unidentified, carried out a suicide bombing there Sunday, the first U.S. citizen believed to have been involved in such an attack.
As many as 3,000 Westerners are believed to have gone to Syria to fight, prompting increasingly aggressive efforts by their home governments to keep them from leaving and to detain them on their return. In Britain, the Home Office has stripped at least 20 jihadists of their citizenship, and police said the number of "Syria-related arrests" totaled 40 from January to March, compared with 25 for all of 2013.
Remarks by Abu Muhajir, 26, and other Westerners fighting in Syria provide some insight into their motivations and outlook, as extremist groups with ties to al-Qaida try to identify, recruit and train men from the United States and Europe to carry out attacks when they return home, according to senior U.S. intelligence and counterterrorism officials.
Abu Muhajir has identified himself on social media as American. He said his grandparents emigrated from Pakistan to North America, where he was raised. He would not directly say he is a U.S. citizen, but said he is not Canadian, and that he had gone back and forth to Syria several times without being stopped.
Abu Sumayyah, a British jihadist now fighting in Syria, says that growing up in Britain, he was a "bad Muslim." He smoked, went clubbing, dated a string of women, took and sold drugs, went on binges for days and worried his mother.
But by the time the war in Syria broke out three years ago, he said, he was a deeply devout man, a self-taught student of Islamic history. Now in his early 30s, he has been fighting in northern Syria for nearly a year. He left Britain quietly without telling his parents, taking a few clothes and some cash.
Experts and academics who track Western jihadists in Syria at the London-based International Center for the Study of Radicalization and Political Violence, have independently identified both men as fighters in Syria, as has Brussels-based researcher Pieter Van Ostaeyen, who blogs about Western jihadists.
Abu Sumayyah was initially reached via Twitter and agreed to be interviewed on condition that his real name not be published. Abu Muhajir was interviewed on Kik, an instant messaging platform for smartphones popular among fighters. He would not divulge his real name.
Abu Sumayyah said he had no intention of bringing jihad back home. He plans to die in Syria, and hopes for a rewarding afterlife, he said.
Abu Muhajir offered a darker view, suggesting jihadis could do more to carry their fight to Western nations.