"Defendant Ward admitted he snuck up on the group and they didn't see him coming," Sexton said. He fired at least six times, she told the judge. One bullet struck a 17-year-old in the left ankle, and another grazed the left foot of another 17-year-old.
Pendleton was hit in the upper back.
"She was able to make it outside of the park and then collapsed on the street," Sexton said. The teen died later that day.
Ward ran back to the car, where Williams was waiting, and the two drove off, the prosecutor said. Police tied the two to the shooting with cellphone records that placed Williams near the park at the time, and surveillance video showing Ward's mother's white Nissan driving back and forth by the park.
Ward admitted his role in the shooting to police in videotaped interviews, and Williams confessed "to a third party witness," State's Attorney Anita Alvarez said later. She did not elaborate.
Pendleton's slaying has drawn national attention, in part because of its proximity to Obama's home and in part because the teen had performed during inauguration festivities. First lady Michelle Obama attended the girl's funeral Saturday, and Pendleton's parents were to join the first lady on Tuesday to listen to the president's State of the Union address, in which he is expected to talk about gun violence.
But although Pendleton has become a symbol of the cost of gun and gang violence, authorities said it also was a just a case of mistaken identity.
"Defendant Ward admitted that the girl, now known as Hadiya Pendleton, had nothing to do with it," Sexton said in court. "She was just there."
Attorneys for the two suspects did not speak much at the hearing but talked to reporters afterward.