Updated

Police are searching for someone they say approached a 6-year-old boy as he rode his bike outside Atlanta and shot him in the chest.

Gwinnett County police said in a Monday statement that "it's imperative" the suspect is apprehended in the Saturday shooting of Ni-Shawn Moore.

Police said previously that the boy was shot during a neighborhood birthday party in the Lawrenceville area, northeast of Atlanta. Police said he's expected to survive.

Police said initial reports were that the boy was shot with a BB or pellet gun, but hospital workers later determined that he was actually shot by a small-caliber bullet.

Police said their investigation has found that someone approached the boy and shot him in the upper chest. They haven't given any possible motives.