An 8-year-old boy has been killed in a rollover wreck due to the lack of a seat belt. Two other occupants, also traveling in the minivan were injured in the crash near the Salton Sea town of Mecca, say California Highway Patrol officers.

The 2006 Toyota Sienna rolled over Monday, July 27, along the northbound lanes of Highway 111, south of Mecca Avenue, with 31-year-old Thermal resident Elizabeth Alvarado and four children aboard..

"Alvarado and an 11-year-old (girl) sustained minor injuries and were transported to Desert Regional Medical Center," according to the written statement of Officer Mike Radford. "A 5-year-old boy and a 2-year-old boy… were uninjured."

The 8-year-old boy -- the only occupant who was unrestrained -- died at the scene. Riverside County coroner's officials have released no information about the boy or the incident at this time.

The cause of the wreck remains under investigation, but CHP officers say alcohol and drugs do not appear to be involved.