Authorities say Tulare County Sheriff's Correctional Deputy Jeremy Meyst was driving a sheriff's inmate transportation van when it crashed on Road 204, south of Highway 198 near the Friant Kern Canal Bridge. The accident happened around 2:30 a.m.
The deputy was transporting two inmates who had been arrested from the Porterville Substation to the Main Jail. One inmate was arrested for possession of a controlled substance and the other was arrested on a DUI warrant.
Two inmates were still in the vehicle and received minor injuries that were treated.
Deputy Jeremy Meyst was raised in the Visalia area. He was a 2001 graduate from Mount Whitney High School.
In statement Sheriff Mike Boudreaux said: "I am heartbroken that we have lost a member of our Sheriff's Department family. My thoughts and prayers are with his family, friends and all of our employees during this difficult time."