PHOENIX -- Police have arrested the individuals who they say were involved in the shooting at Cesar Chavez High School on January 31, 2014.
Details were released by Phoenix Police Chief Daniel Garcia and Maricopa County Attorney Bill Montgomery at a news conference on Thursday afternoon.
Montgomery said the individuals are 23-year-old Deric McWilliams, 20-year-old Daryl Fulbright, 20-year-old Jontrell Wooten and 17-year-old Jordan Norman.
The Phoenix Police Department's Gang Enforcement Unit investigated the incident.
Police said the four men are known members of rival gangs and got into a confrontation that night.
The arrests followed indictments by the Maricopa County Attorney's Office. The men are facing charges related to gang activity and weapons violations.
The high school near 43rd Avenue and Baseline Road was hosting a boys' varsity basketball game against a rival high school, Betty H. Fairfax, when gunfire erupted outside just after 8 p.m.
Police originally believed the shots were fired into the air but later said the suspects were shooting at each other.
Investigators did not find any damage to school buildings.
No one reported being hit by gunfire but there were injuries when students and other spectators stampeded out of the gym.
"It sort of underscores the fact that when you've got gangs who want to engage in violence, they don't always choose places and opportunities where it's not going to impact other folks in the community," Montgomery said at the news conference.
Students said there had been threats over social media during the week leading up to the game.
New safety measures have been implemented since the incident.
"Our schools are the safest places in our community and they are a place where our students are being prepared for college and career success," said Dr. Kent Scribner, the Phoenix Union High School District superintendent.