Police arrested 19-year-old Yousuf Mohammad Aziz from Antioch.
Police don't know whether he was the actual shooter or the driver in Wednesday's drive-by which left a 16-year-old boy in the hospital recovering from a gunshot wound.
The shooting took place on a side street near the Deer Valley High School campus, just as the victim and his friends were walking to school.
Police also arrested a second person on Thursday morning that someone identified as the shooter, but police now say they're not sure whether that person is actually connected to the crime. He remains in custody.
Investigators say the shooting appears to be gang related and that Aziz and the victim knew each other.
"Mr. Aziz and our victim both belong to rival gangs, and that appears to be the motivation behind it," said Lt. Leonard Orman from Antioch Police Department.
Police said when they spotted Aziz last on Wednesday night, he took off running. During the chase police entered a house where they located an assault rifle. Authorities don't believe it's connected to the shooting, but the home's owner was arrested.
The pending charges against Aziz include assault with a firearm and possession of a firearm by a criminal street gang member. He's being held on $425,000 bail.