Six people were killed and two were hospitalized in a suspected DUI crash in rural Napa County Sunday evening, the California Highway Patrol said.

The single-vehicle crash happened shortly before 6 p.m. along Pope Valley Road, near Pope Valley Union Elementary School.

Deputies with the Napa County Sheriff's Office were first to arrive, finding a Toyota Sienna minivan off the side of the road with multiple people inside, the CHP said. 

An investigation determined that the minivan was traveling south on Pope Valley Road when the driver allowed the vehicle to leave the roadway and strike a tree, the CHP said. 

Six people were pronounced dead at the scene, the CHP said. The Napa County Coroner's Office said all six are believed to be farmworkers either from or near the Stockton area in the Central Valley.

Two of the deceased were identified by the coroner's office as Loreto Ricardo Hernandez, 42, and Fernando Silverio, 34, both of Stockton.

The driver and another occupant were airlifted to a nearby hospital with major injuries, officers said. 

The CHP said the driver was placed under arrest at the hospital on suspicion of DUI causing injury/death. Authorities identified him as Norberto Celerino, 53, also a Stockton resident.

Pope Valley Road was closed for several hours during the investigation.