It is the deadliest attack by ISIS on the West in several years. But still, almost a week later, the group also known as Islamic State has yet to issue its trademark claim of responsibility for the horrific New Year’s violence in New Orleans.

Recordings and interviews detail Shamsud-Din Jabbar’s growing discontent with American society and increasing isolation even within his local Muslim community.

A 9/11-style attack on the U.S. is unlikely now, he said, because ISIS and al-Qaida’s capabilities have been so degraded by U.S. and coalition efforts in the Middle East. “So they've looked to inspire individuals that already have access and in some cases,