Updated

Police in Philadelphia were searching for a suspect in connection with a shooting that injured a boy and a girl hanging out with a group of fellow students in a high school gym Friday.

The shooting happened at the Delaware Valley Charter High School in north Philadelphia around 3 p.m., authorities said.

Police found one boy wanted in the shooting near his home. Police Commissioner Charles Ramsey said the boy was questioned and released from custody and is no longer a suspect.

A second boy turned himself in to police Friday night. A third was still being sought Saturday.

The two victims, both reportedly 15-year-old students, were each shot in the arm and taken to a local hospital. One was later released and the other was listed in stable condition.

Ramsey said surveillance video showed a group of students hanging around when the shooting happened.

It was unclear if the shooting was accidental or intentional but it "doesn't look like an active shooter type of situation," he said.

Former student Donte Jenkins, who graduated last year, said there were metal detectors at the entrance and he couldn't figure out how someone could have gotten in with a gun.

"It was always a safe environment," Jenkins said. "It was never a bad environment. I don't know how this really happened."

The school was placed on lockdown and secured by SWAT officers checking each room. Students were searched and released one by one.

Terry Starks, an outreach supervisor for the gun control group Philadelphia CeaseFire, was outside the school Friday evening and was trying to contact his son, a student.

"I'm a gunshot victim so I already know how being shot affects the family," he said. "I feel bad for the mothers and the fathers of these children that got shot. ... Your heart drops."

A spokesman for the school district didn't immediately respond to a call seeking comment. The president of the charter school's board of trustees said he didn't have any additional information about the shooting, not the only U.S. school shooting this week.

A 12-year-old boy is accused of opening fire with a shotgun at a New Mexico school Tuesday and seriously wounding two students.

The Associated Press contributed to this report