CHICAGO (CBS) — A family is demanding justice after a 12 year-old boy was shot and killed getting snacks with a relative.

The child’s mother broke down as the family pleaded with the killer to come forward.

Twelve-year-old Demetrius Townsel, Jr. was shot and killed Saturday night in Gary. Townsel, his twin brother and two other children went to a gas station with a relative to pick up snacks.

They had just left when someone started shooting at their car near 26th Avenue and Pierce Street. A bullet hit Townsel in the head. His twin brother Darius tried to save his life by putting pressure on the wound.

Gary police said they’ve been canvassing the area, and asking for the public’s help. A $2,000 reward is being offered for information leading to an arrest.

Those with information can call the Gary Metro Homicide Unit at 219-755-3855.  People can also leave tips anonymously by calling 1-866-CRIME-GP.