A New York City man who traveled to Syria to join ISIS before escaping months later called the experience "the worst decision I’ve ever made in my life."
In an exclusive interview set to air Thursday on "NBC Nightly News with Lester Holt" ahead of a longer feature on "Dateline: On Assignment" Sunday evening, the man identified as Mo told NBC News' Richard Engel about how he went from being a student at one of the nation’s top colleges to the ranks of the violent terrorist organization in Syria.
"At one point towards the end as things were getting more and more serious, I did see severed heads placed on spiked poles," he told Engel.
Mo, who traveled to Turkey to join ISIS before he eventually escaped, was detained by federal authorities and is in custody and cooperating with counterterrorism efforts. He told Engel that he agreed to take the interview to combat the organization’s propaganda machine.
"The Islamic State is not bringing Islam to the world, and people need to know that," he said. "And I'll say that…till the day I die."