Man in custody after 15-year-old boy fatally shot in Philadelphia's Port Richmond section

PHILADELPHIA (WPVI) -- Philadelphia police say a 40-year-old man is in custody after allegedly shooting and killing a 15-year-old boy Saturday night in Port Richmond.

Police said the shooting happened near the Sunoco gas station at Richmond Street and Castor Avenue just before 7 p.m. The boy was with a group of juveniles when the man fired a single gunshot, striking the teenager near his back or side, according to detectives.

"It's certainly a very tragic incident. We have a 15-year-old male whose life has been cut short, and we don't know the reason for that," Philadelphia Police Inspector D.F. Pace said.

Investigators are now working to determine what led to the shooting.

"It's unclear what exactly might have precipitated it," Pace said.

After being shot, the teenager managed to run about a block before collapsing on a sidewalk in the 3600 block of Richmond Street, police said.

Two medical professionals who were driving by stopped to help.

"They then also sprang into action and performed life-saving measures. Unfortunately, they were not enough to save him, but they were enough to allow officers to arrive, take him to the hospital and try to get him the best care possible," Pace said.

The boy was taken to a hospital, where he was pronounced dead shortly after arriving.

Police said officers were able to quickly gather information about the shooting and identify a suspect. They found the man at his parents' house near the scene.

"Officers very quickly were able to again gather information on what exactly happened, and who might have been responsible, and based on that information they went to a home just about a block away and located the offender," Pace said.

As the investigation continues, police will review surveillance video that captured the shooting. Investigators said the footage is a key piece of evidence as they work to determine a motive.