The suspect was not identified because of his age.
The shooting happened around 10:00 p.m. on Friday, September 20th in the 600 block of North Van Buren Street.
Police say the 17-year-old victim was walking when he was approached by the 12-year-old.
The younger boy allegedly demanded the victim's cell phone and the two started to struggle.
That's when the 12-year-old allegedly shot the teen in the leg.
The 12-year-old was arrested on Wednesday and charged with possession of a firearm during the commission of a felony, robbery and assault.
Furthermore, police say the child was on probation for robbery.
He was arraigned and committed to the New Castle County Detention Center in lieu of $150,000 cash bail.