Police said the child was walking on Harriet Drive near Violet Way, a few blocks from Gregory Gardens Elementary School, around 7:30 a.m. when a man approached from behind and grabbed the juvenile's buttocks. The suspect then sprinted from the scene and was last seen running south on Shirley Drive, according to police.
Officers searched the area but were unable to locate the man.
However, police said, the juvenile victim was able to snap a photo of the suspect as he fled.
He is described as a Hispanic man in his 40s who was wearing a blue Dodgers windbreaker, a gray hooded sweatshirt and blue jeans, according to police.
Anyone with information about this case is asked to call Pleasant Hill police at (925) 288-4600.