Steven Jones
Suspected gunman Steven Jones, a freshman at Northern Arizona University in Flagstaff is shown in this booking photo released on October 9, 2015. An 18-year-old student killed one peer and wounded three others when he opened fire during a confrontation on the Northern Arizona University campus early on Friday before being arrested, in another shooting to hit a U.S. school, authorities said.REUTERS/Northern Arizona University/Handout

Northern Arizona University campus shooter Steven Jones was formally charged with second-degree murder in a campus shooting that left three other students injured. Jones, a freshman at the university, was initially charged with first-degree murder in the death of 20-year-old Colin Brough.

According to The Associated Press, that charge was downgraded in a complaint released on 14 October, which stated that Jones did not act with premeditation. Jones now faces up to 25 years in prison. The 18-year-old now also faces six assault charges—two for each of the three other students also shot during the incident.

The three injured students were identified as Nicholas Prato, Nicholas Piring and Kyle Zientek. Prato and Piring have been released from Flagstaff Medical Centre, while Zientek's condition is unclear, the AP reported. All four victims in the shooting were members of the Delta Chi fraternity.

Jones told investigators he was acting in self-defence during an altercation in the early hours of 9 October. He also claimed he was pursued by several people when he ran to his vehicle, where he told them he had a gun. However, Deputy County Attorney Ammon Barker said the shooter could have walked away, but instead decided to grab his weapon and "went back into the fray."

A university spokeswoman said that the shooting happened in a car park near a residence hall for the Greek fraternities and sororities around 1.20am. Following the shooting, Campus Police Chief Gregory Fowler said: "We don't know the facts yet about what brought them together, or what caused the confrontation."

The AP reported a preliminary hearing is scheduled for 19 October in Flagstaff Justice Court. Jones was previously placed on a $2m cash-only bond. Brough's death was declared a homicide by the medical examiner. He was shot twice, once in the chest and once in the right shoulder.