Riverside County Sheriff's Department officials said David Loperena, 26, turned himself in. He is suspected of killing Anthony Ochoa as the child and his family crossed the street Tuesday night.
The family was in the crosswalk when the driver of a pickup truck ran the stop sign near Summer Avenue and Langstaff Street. The driver fled the scene without stopping, authorities said.
Anthony was rushed to the hospital, but did not survive. He was a third grader at Elsinore Elementary School, right across the street from where he died.
Authorities had described the suspect's vehicle as a red Chevrolet truck with chrome rims and a broken windshield.
A mugshot of Loperena was not available.