I'd been communicating with Russell Dennison almost daily for more than six months when his messages suddenly stopped coming.

Dennison was a devout Muslim. He believed the time and place of his death were predetermined, that if a bomb were meant for him, it would kill him, regardless of anything he might do to avoid it. That bomb found him in the spring of 2019 in Baghuz, a small village in eastern Syria near the border with Iraq. I learned of his death months later, after a witness told Dennison’s Syrian wife, and she told me.

A red-bearded American who was raised Catholic in the Pennsylvania suburbs, Dennison was among the first Americans to join the Islamic State, or ISIS. I had initially tried to contact him in 2014, after hearing rumors that he’d left the United States to fight in the Syrian civil war. For years, I received no response. Then in August 2018 — after fleeing Raqqa as U.S.-led coalition forces approached ISIS’s de facto capital — Dennison emailed me. He wanted to talk.