Police on Saturday arrested a juvenile male in connection with a shooting Friday at Benjamin Franklin High School.
No one was injured.
Charges against the juvenile, believed to be the shooter, were pending, police said.
The boy's name is not being released because he is expected to be charged as a juvenile.
At about noon Friday, police responded to the high school on the 500 block of North Broad Street in Spring Garden for a report of gunshots.
Police found one .45-caliber fired cartridge casing and one projectile in the west stairwell.
Police said several witnesses were taken to the Central Detective Division to be interviewed. Based on those interviews, it was determined that several students were involved in a fight in the hallway of the fourth floor of the school and that a gunshot was fired, police said.
Police said a search warrant was then obtained and served at the juvenile male's home, where he was taken into custody.
The boy was officially arrested at 1:30 a.m. Saturday.
Sgt. Eric Gripp, a police public affairs spokesman, said Saturday that he did not know if the youth was a student at the school and did not have his age.
After the shooting Friday, three students were taken by police in handcuffs from the school shortly before 2 p.m.
Gripp said those students were eventually released. He did not know if they participated in the fight or if they were potential witnesses.
The juvenile who was arrested was not one of those three students, Gripp said.
The school was placed on lockdown Friday from about noon to shortly before 4 p.m., he said.
Gripp said a gun was recovered Friday from a classroom inside the school, but it was not immediately clear if that was the gun used in the shooting.