A 15-year-old has been charged with first-degree murder in Delaware County on Wednesday.
Samir Austin is accused of shooting another 15-year-old with a ghost gun he bought online, police say.
Authorities believe Austin fired shots into a corner store in Darby, Pennsylvania on Monday afternoon.
He was arrested on Tuesday, just 16 hours after the shooting.
An 18-year-old was also injured by the gunfire.
Investigators in Delaware County say Ausrin bought the untraceable weapon as a kit gun, assembling it with the specific intent to kill.
Prosecutors say they are trying Austin as an adult for this crime.