If he had been convicted at trial, Kohberger could have faced execution by firing squad. That capital punishment method is newly legal in Idaho because of the ongoing nationwide shortage of the lethal injection drugs, as major pharmaceutical suppliers have withdrawn from the capital punishment market.

Bryan Kohberger appeared expressionless as a judge asked if he murdered four Idaho college students in their off-campus home, answering “yes” to each name called out in the courtroom Wednesday.

With a series of “yes” replies to a judge, a man accused of killing four Idaho college students pleaded guilty in exchange for life in prison and no death penalty. But left untold so far: What motivated Bryan Kohberger to commit the middle-of-the-night knife attacks and why those victims?