A 16-year-old boy is dead and another remained in critical condition on Tuesday after a shooting in Philadelphia, near an area charter school.

The gunfire erupted in the early hours of Monday morning, along the 200 block of East Duncannon Avenue not far from Olney Charter High School, NBC Philadelphia reported.

Before they reached the scene, officers were flagged down around 2:30 a.m. by a driver traveling on Whitaker and Hunting Park avenues. The motorist had been transporting two wounded teens to the hospital, said police, who did not provide further details on the matter.

One of the teens was shot in the head and arrived at the nearby Temple University Hospital in extremely critical condition. He was pronounced dead a short time later, according to law enforcement. The second victim was struck in the ear and left shoulder. He was taken to St. Christopher’s Hospital for Children, where he remains in critical condition.

More than 20 shell casings were recovered at the scene, police said.

“It does appear that they were both shot at close range,” Inspector D.F. Pace, with the Philadelphia Police Department told ABC 6. “It does appear that they were targeted.”

So far, no arrests have been made in connection with the deadly violence. Police believe a total of four suspects were involved in the shooting, and that they fled the scene in an SUV.

Neither the victims nor the suspects have been identified. What occurred in the moments leading up to the gunfire was also unclear.

Anyone with information about the shooting have been urged to contact Philadelphia police at 215-686-8270. Tips can also be submitted anonymously by calling or texting 215-686-TIPS (8477).