According to last year’s Program on Extremism Pentagon report, at least 64 Americans have left the United States for Iraq or Syria in order to join the terror group known as the Islamic State. As compared to the thousands of Europeans that have left their homes to join ISIS, that figure is rather modest, perhaps contributing to just how unsettling it can be to hear Americans sing the praises of the violent regime.

Such has been the case for 34-year-old Warren Christopher Clark, a Texan who once worked as a substitute teacher, but was recently captured by U.S.-backed Kurdish forces in northern Syria, where Clark claims he offered to work for the Islamic State as an English teacher. Clark, who remains in Kurdish custody, has been open about his decision to leave the United States and seek out the Islamic State, offhandedly comparing it to living in Texas.

“I wanted to go see exactly what the group was about, and what they were doing,” he said. “Of course I saw the videos. I think with the beheadings, that’s execution. I’m from the United States, from Texas. They like to execute people, too. So I really don’t see any difference. They might do it off camera, but it’s the same.”

According to Clark, the FBI has been in contact with him since his capture by Syrian Democratic Forces, but he does not know whether or not he’ll be extradited. According to the former substitute teacher, he never fought for ISIS, though he did have a number of interactions with them. He claims to have been detained by ISIS nearly a dozen times over his refusal to “take up arms,” though he went on to claim that he suffered no abuse at their hands. He did, by his own admission, offer to help the group by teaching them English.

Those claims are supported by the discovery of Clark’s resume and cover letter in a house in Iraq, under the alias Abu Muhammad al-Ameriki. In the letter, Clark says that he’s an English teacher who wants to find work in ISIS-controlled territory.

“I was born and raised in the United States and have always loved teaching others and learning from others as well. My work background is largely in English and I consider working at the University of Mosul to be a great way of continuing my career,” the cover letter reads. The resume and letter were tied to Clark thanks to his email address, education credentials, and work history.

Clark has since acknowledged moving to Mosul from Turkey in 2015, a decision he said was motivated by a desire to better understand the terrorist group.

“I wanted to learn more about the ideology. I’m a political science major, global business minor. I like politics. I like travel, world events. That’s what I wanted to do,” he said.

He went on to recount how difficult his time in Mosul was, seemingly distraught at the possibility of his own death, despite admitting to witnessing numerous executions conducted by ISIS members during his time there.

“It was a place that was constantly being bombed,” he said. “You were always on edge. Day and night, just bombs and airstrikes. You sleep in the middle of the day. I spent most of my time living in a mosque. I just remember every day hoping not to get bombed.”