Darrin Manning is still having trouble walking a week later. He suffered a serious injuries to his genitals. He claims his injuries came at the hands of a Philadelphia police officer during a recent arrest.

POLICE in Philadelphia have launched an internal investigation after a teenager allegedly suffered a ruptured testicle during a pat-down by a female officer.

Darrin Manning, 16, had emergency surgery on his genitals after the incident and doctors say he may never be able to have children.

The straight A student was walking with a group of friends to an after-school basketball game when he was stopped by a group of police officers.

Manning told local TV station Fox 29 he was stopped for no reason by Officer Thomas Purcell at the corner of 15th and Girard streets and that one of the officers assaulted him while he was handcuffed.

"She patted me down again, and then I felt her reach, and she grabbed my butt. And then she grabbed and squeezed again and pulled down. And that's when I heard something pop, like I felt it pop," Manning said.

The teen spent eight hours in jail after the alleged attack, but police say he never reported any injuries.

According to philly.com, Mannning admits that one of his teammates may have said something smart to Officer Purcell, who he claims was "staring them down".

The teen said when Officer Purcell, who is white, approached the group, they ran.

Police records state that Officer Purcell observed a group of males covering their faces with ski masks and running. The students say there were not wearing ski masks, just their school scarves, philly.com reports.

The police report said Manning - who denies retaliating - began fighting with the officer, striking him three times and ripping off his radio.

Officers said the teen did not complain of any pain during his eight hours in custody, charged with assaulting an officer, resisting arrest and reckless endangerment.

But the teen underwent surgery the next day for his injuries.

A witness told philly.com the police indicent was excessive.

"There were all these cops and cops cars, and one kid," she said.

The incident left Manning in a wheelchair for days while recovered from his injuries.

A police spokesman said if internal affairs were found the officers acted improperly, they would be disciplined.

"I think we have proven we will not tolerate that kind of behavior," he said. "We are not looking to make a divide between police and the community."