Thirty years ago this April 19, TV viewers looked on as Mount Carmel—the sprawling Branch Davidian compound on a bleak stretch of prairie outside Waco—was engulfed in flame and smoke. The destruction of the rickety settlement, familiar after two months of intense media coverage, marked the fiery end of a 51-day siege which left four federal agents and 82 Branch Davidians dead, including 23 children and the group’s messianic leader, David Koresh.

The siege also left troubling questions: How did it all go so badly wrong? Who was to blame? What motivated people of faith—among them a Harvard-trained lawyer, a one-time University of Hawaii Ph.D. student, and a former middle school teacher—to kill and die at the behest of a man authorities portrayed as a delusional “cult” leader, a religious con man?