Nikolas Cruz pleaded guilty on Wednesday on all charges related to the 2018 shooting at Marjory Stoneman Douglas High School in Parkland, Florida, which left 14 students and three staff members dead.

Cruz, 23, pleaded guilty to 17 murder counts and 17 counts of attempted first-degree murder for opening fire at the high school three years ago. Circuit Judge Elizabeth Scherer will shift the trial to a penalty phase, in which a 12-member jury will determine Cruz’s punishment.