A man has pleaded guilty to third-degree murder in the shooting death of a recent high school graduate during what police say was a road rage confrontation last year in southeastern Pennsylvania.

Twenty-nine-year-old David Desper entered the plea Wednesday in Chester County in the death of 18-year-old Bianca Roberson.

Police say the two jockeyed for space in the merger of a highway lane in West Goshen Township in June 2017 before Desper shot Roberson in the head, and her car veered off into a ditch and hit a tree. Desper turned himself in four days later.

The plea came a week before criminal proceedings were scheduled to begin. Desper was originally charged with first- and third-degree murder, criminal homicide, possession of an instrument of crime and reckless endangerment.