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?

After a surprise plea deal agreement, Bryan Kohberger appeared in court on Tuesday and admitted to killing four University of Idaho students: Madison Mogen, Kaylee Goncalves, Xana Kernodle and Ethan Chapin.

After two agonising years of court hearings, headlines and documentaries, Bryan Kohberger has admitted to the “wilful, unlawful, deliberate” murder of four US college students inside their Idaho home.