It happened at the Church of God of Prophecy in the 3300 block of Covington Drive in Decatur.
DeKalb police spokesman Jason Gagnon said it appears the bullet came through the church's roof and struck the child in the head. DeKalb police told Channel 2 Action News that they are actively working leads in the case.
"It's so hard ... he was my only child," said Nathalee Peters, the child's mother.
Nathalee Peters told Channel 2 Action News reporter Tony Thomas that her family was waiting for a concert to begin at the church when her son, Marquel Peters, 4, was struck by the bullet. It happened just twenty minutes into the new year.
"I saw his Nintendo game fall on the floor, and I heard a sound and I heard him scream a little bit and I looked around and all I saw was blood coming from his head," said Nathalee Peters.
Family and friends are now making a plea for anyone with information to come forward. The area surrounding the church is full of houses and an apartment complex.
"They may have just gone out, fired a few gunshots into the air celebrating the new year having a good time and gone back to their family not knowing what happened, but a little boy is lying in a morgue today," said Pastor Lloyd Phipps.