A suspect is now in custody a day after two students were shot inside a Philadelphia high school.

The shooting happened on Friday just before 3:30 p.m. at the Delaware Valley Charter School at 5201 Old York Road in the Olney section of the city, Philadelphia Police say.

"Two kids, a male and a female, both shot in the arm" is the call that went out over police radio minutes after the shooting on Friday afternoon.

"A school is supposed to be a safe environment. Are you kidding me? Two kids just got shot," shouted Frank Thorne, whose daughter was inside the school at the time of the shooting. "How was a child, or whoever, [able to] bring a gun up in the school?"

A teen boy, who attends the school, pulled out a handgun inside the school's gymnasium and then the weapon fired, according to officials.

An 18-year-old girl and a 17-year-old boy were injured in the shooting, which took place near the gymnasium, police said. The bullet struck the rear of the girl's left arm, exited her bicep and then struck the boy in the shoulder, according to police.

Both victims were rushed to Albert Einstein Medical Center, which is just a block north of the high school.

The girl was discharged from the hospital around 6 p.m., but the boy remains hospitalized. He is currently in stable condition.

"We are thankful that our students are in good condition and recovering from this incident," school officials said in a statement released Saturday afternoon.

Philadelphia Police Commissioner Charles Ramsey says there were seven students inside the gym when the shooting happened and that the entire incident was caught on surveillance video.

THE SUSPECTS

At the height of the investigation immediately following the shooting, Philadelphia Police used surveillance video to identify alleged suspects. Police also say they received information from school security and school officials.

Based on that information, police say they identified a 15-year-old student from South Philadelphia as a suspect.

Police descended on the home of the student and brought him in for questioning. Officials said they thought he was either the shooter or was with the shooter.

But hours later, that teen was released and, police say, will not be charged. According to police, the boy was not involved in the shooting. They also claim the security officials provided inaccurate information regarding the boy.

The school did not address the police allegations of inaccurate information in its statement.

Family members of the teen, angry over his implication, told NBC10 he was a "straight A student." That same family member, an uncle who wished to remain anonymous, said his nephew's involvement in the shooting was some kind of mistake.

After examining the surveillance video and conducting numerous interviews, police identified two suspects in the shooting.

A 16-year-old boy was taken into custody and questioned at Philadelphia Police's Northwest Detective Division. Investigators initially said they considered him a co-conspirator, but did not believe he was the shooter. He was questioned and then released Saturday morning. He has not been charged.

Police filed charges against a second suspect, a 17-year-old boy. The teen turned himself in on Saturday and is charged with two counts of aggravated assault and other related offenses.

"It's just like any other investigation, now we're able to talk with the people that were shot, the victims, able to talk with some of the kids that may have seen what took place," Ramsey said.

SEPTA Police searched trash cans and station concourses to see if the gun used was dumped. So far, those searches have been futile.

THE SCHOOL & SHOOTING RESPONSE

Delaware Valley Charter School is one of 87 charter schools in Philadelphia. Charter schools are independent of the School District of Philadelphia. The school serves more than 600 students in grades 9 through 12.

The school was placed on lockdown following the shooting and was quickly secured.

"We had good response and were able to lock this down very, very quickly and get information very quickly as to who the suspect was and be able to locate that person very quickly and so this one worked out for us," Ramsey said.

Officials say students were searched and then released on a one-by-one basis. The school was completely cleared at 5:30 p.m.

Parents told NBC10 reporters on the scene that there have been several fights at the school recently and that they had concerns about safety.

Police say the school does have security. The building is also equipped with metal detectors, so investigators are trying to figure out how the student was able to get the gun into the school.

"They go through metal detectors. You have to go through everything to get into the school even as a parent," said Gina, who did not want to share her last name. "I have to go through metal detectors."

"Clearly a breech of security of some kind," said Ramsey. "Don't know exactly how it happened, but kids shouldn't be able to get a gun in school."



Along with thanking parents for their support and understanding, school authorities say they will "continue to follow our mission making Delaware Valley Charter High School a S.A.F.E place to learn."

The acronym "S.A.F.E." stands for scholarship, attitude, focus and excellence, according to the school's website.

School officials say, "We will continue to be committed to making sure that the safety of our children and staff is taken seriously inside and outside of school."

Contact Vince Lattanzio at 610.668.5532, vince.lattanzio@nbcuni.com or follow @VinceLattanzio on Twitter.