Believing he was answering a holy call, Harry Sarfo left his home in the working-class city of Bremen last year and drove for four straight days to reach the territory controlled by the Islamic State in Syria.
Mr. Sarfo said he had started doubting his allegiance to ISIS during his training, after seeing how cruelly they treated those who could not keep up.
He began plotting his escape, which took weeks and involved sprinting and crawling in a field of mud before crossing into Turkey. He was arrested at Bremen Airport, where he landed on July 20, 2015, and he voluntarily confessed. He is now serving a three-year term on terrorism charges.
The intelligence documents and Mr. Sarfo agree that the Islamic State has made the most of its recruits’ nationalities by sending them back to plot attacks at home.
Yet one important region where the Emni is not thought to have succeeded in sending trained attackers is North America, Mr. Sarfo said, recalling what the members of the branch told him.
Though dozens of Americans have become members of the Islamic State, and some have been recruited into the external operations wing, “they know it’s hard for them to get Americans into America” once they have traveled to Syria, he said.
“For America and Canada, it’s much easier for them to get them over the social network, because they say the Americans are dumb. They have open gun policies,” he said. “They say we can radicalize them easily, and if they have no prior record, they can buy guns, so we don’t need to have no contact man who has to provide guns for them.”