A 2-year-old San Bernardino boy died at a Riverside hospital Monday afternoon after his grandmother accidentally ran him over in a truck, police said.

Alex Hernandez died at Riverside Community Hospital at 12:24 p.m., according to Riverside police Sgt. Randy Eggleston. The accident occurred at 11:59 a.m. behind the grandmother's home in the 2000 block of Cridge Street.

The boy's grandmother, Juana Jaimez, 49, initially told police the child had been struck by a car while in an alley behind her house. She had said she opened a gate that leads into a back yard, then later saw the boy lying in the alley.

Police had received conflicting stories about what had happened. Monday night, after talking to detectives, Jaimez said she had run over Alex in a truck, Eggleston said.

Jaimez has not been arrested or cited. Police will submit the case for review to the Riverside County district attorney's office, Eggleston said.

Alex's mother had dropped him off at his grandmother's house before she went to work, Eggleston said.

The child's relatives declined to comment.