Police think a driver tried to save the boy from a fight.
Dominic Robinson, who was slain earlier this month, had testified about tensions between police and residents.
The shooting occurred Thursday night near Naylor Road and Alabama Ave.
Police said the shooting occurred Wednesday afternoon.
A roundup of news from around the region.
Delonta Daniel is charged in the death of a Hyattsville man last month.
The motive for the afternoon attack in the business district remains unclear, authorities said.
The suspect was charged with first-degree murder in the killing last month of a 45-year-old man.
Police are investigating the latest homicide in the Burrville neighborhood.
The investigation stretched from Jacksonville to Baltimore as authorities searched for answers in the wake of the violence.