A 67-year-old man was beaten and robbed in the parking lot of the Graton Resort & Casino in Rohnert Park Tuesday morning, an attack that left him with severe head trauma, the Sonoma County Sheriff's Office said.

Deputies were called to the scene around 6:30 a.m. and found that he had been struck in the head with an unknown weapon and robbed of an unknown amount of cash and other property, according to a departmental release.

The man, whom deputies did not identify, told investigators from the Violent Crimes Unit that at least two people were involved in the assault.

He was transported to Santa Rosa Memorial Hospital.

Deputies and casino security are investigating the attack.

Victims identified in Sonoma, Napa, Mendocino fires

Sonoma County:

Karen Aycock, 56, Santa Rosa

Christina Hanson, 27, Santa Rosa

Linda Tunis, 69, Santa Rosa

Carol Collins-Swasey, 76, Santa Rosa

Lynne Anderson Powell, 72, Santa Rosa

Arthur Tasman Grant, 95, Santa Rosa

Suiko Grant, 75, Santa Rosa

Donna Mae Halbur, 80, Larkfield

Leroy Peter Halbur, 80, Larkfield

Valerie Lynn Evans, 75, Santa Rosa

Carmen Caldentey Berriz, 75, Apple Valley (vacationing in Santa Rosa)

Michael John Dornbach, 57, rural Calistoga

Veronica Elizabeth McCombs, 67, Santa Rosa

Carmen Colleen McReynolds, 82, Santa Rosa

Sharon Rae Robinson, 79, Santa Rosa

Mike Grabow, 40, Santa Rosa

Daniel Martin Southard, 71, Santa Rosa

Lee Chadwick Roger, 72, Glen Ellen

Mendocino County:

Roy Howard Bowman, 87, Redwood Valley

Irma Elsie Bowman, 88, Redwood Valley

Kai Logan Shepherd, 14, Redwood Valley

Napa County:

George Chaney, 89, Napa

Edward Stone, 79, Napa

Charles Rippey, 100, Napa

Sara Rippey, 98, Napa

Sally Lewis, 90, Napa

Teresa Santos, 50, Napa

Garrett Paiz, 38, Missouri