FLAGSTAFF, Ariz. (AP) -- A prosecutor on Tuesday portrayed a former Northern Arizona University student as a killer who carried out "his own deranged sense of justice" when he opened fire on a group of people during a drunken fight near the campus.
The account came during closing arguments in the murder trial of 20-year-old Steven Jones, who killed one student and wounded three others in what he said was self-defense after being punched in the face just a few weeks into his freshman year in 2015. Jurors began deliberating after closing arguments were finished.
The incident in Flagstaff came at a time of heightened anxiety over school shootings, occurring just days after a gunman killed nine people in a writing class at a community college in Oregon.
>>VIDEO: Closing arguments in NAU shooting trial [Viewer discretion advised]
The Arizona incident started as a late-night drunken brawl among fraternity members and ended in gunfire after Jones went to his car, retrieved a gun and opened fire as the fight continued, authorities say.
"The defendant didn't just retaliate with his fists. He escalated it, and he came back with a gun. He wanted to teach someone a lesson," prosecutor Ammon Barker said. "Again, this is not self-defense."
Barker showed the jury autopsy photos of Colin Brough, who was killed, in arguing that Jones should be found guilty of murder.
Attorney Burges McCowan, who represents Jones, said his client waited until the last possible moment to open fire as he was being chased by upper classmen after he was hit in the face.
"He didn't want to take the chance. He had to stop them," McCowan told the packed courtroom.
McCowan said Jones holstered his gun after shooting Brough and another student who chased him and started to provide aid to Brough. But he was then attacked by others and shot two other students in the struggle, McCowan said, characterizing the confrontation not as a fist fight but rather a "mob attack."
Prosecutors say Jones could have walked away from the fight without resorting to gunfire, but chose instead to go to his car to retrieve a gun and return to the fray.
"What he did afterwards has nothing to do with self-defense and has everything to do with retaliation," Barker said. "He wanted to be the judge, jury and executioner."
Jones, dressed in a dark gray suit and wearing plastic-framed glasses, kept his eyes trained on the lawyers as they made closing arguments.
He testified earlier in the trial that he was accosted by a drunken group of strangers, punched in the face and chased by some members of the group, prompting him to run to his vehicle and get a .40-caliber handgun.
Jones had said he went back toward the group and fired his gun but didn't mean to hurt anyone. He testified he fired several shots "to stop the immediate threat that was coming at me."
The shooting also wounded Nicholas Piring, Nicholas Prato and Kyle Zeintek. None of the victims was armed.
Zeintek, who lost a kidney and part of his intestine due to his injuries, had testified that he tried to run away moments before he was shot twice in the back.
Prosecutors didn't seek the death penalty. A first-degree murder conviction carries a maximum penalty of life in prison.
Jurors have the option of returning lesser verdicts that carry lighter sentences, such as second-degree murder and manslaughter.