Warren Christopher Clark told NBC News that he has no regrets about his decision to join the Islamic State.

The 34-year-old former substitute teacher from Texas said he sought out the group in June 2015.

The resume and cover letter were discovered in a home in Mosul, Iraq, and eventually obtained by George Washington University's Program on Extremism. Clark told NBC he sent the resume from Iraq, where he was living at the time, because he needed a way to support himself.

"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 in the interview .

He claims he did not personally take up arms or fight for the Islamic State, but he became very familiar with the sound of airstrikes.

"It was a place that was constantly being bombed," he said in the interview. "You were always on edge. Day and night, just bombs and airstrikes."

Clark said over the course of three years in the caliphate, he witnessed "executions and crucifixions." He compared the executions conducted by IS fighters to those in his home state of Texas.

"I'm from the United States, from Texas," he said in the interview . "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 NBC , the Texan converted to Islam, but it is not clear when. He was captured by US-backed Kurdish forces and is being held in their custody in Northern Syria.

Agencies