Tequila Forshee was getting her hair braided Thursday night at her grandmother's home in preparation for her first day of seventh-grade.
Grandmother Tawanda Brown told The Miami Herald she heard dogs barking before a hail of bullets tore through her house.
One bullet pierced Tequila's head and she was pronounced dead at midnight.
Miami Gardens Mayor Oliver Gilbert urged any witnesses to come forward at a press conference Tuesday afternoon.
Police said they are searching for four male suspects ages 15 to 18 who were riding two bicycles in the area.
A fifth suspect may have fled on foot, police told the Herald.
An anonymous donor put up $25,000 for the reward fund, and Crime Stoppers offered $5,000.