Nelson's body was found on Washington Boulevard and Brandon's body was found on North Lotus. But police say they were victims of the same shooting.
Nelson's grandmother urged the shooter to come forward Sunday.
"[If] you can just shoot two people down, and just walk away, that's a problem. That's a problem. You've got to have a heart, you know, how can you just take somebody's life? Take something you didn't give. It hurts so bad," Vaughencil Nelson said.
Chicago police have not made any arrests.