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?

Bryan Kohberger pleaded guilty to the murders of four University of Idaho students as part of a plea deal to avoid the death penalty more than two years after the slayings shocked the nation and touched off a coast-to-coast manhunt.

NBC News' Gadi Schwartz presents a timeline following how Bryan Kohberger went from criminology student to killer. Kohberger pleaded guilty at an Idaho court to homicide charges as well as one count of burglary after he stabbed four university students at their home near the Washington border.