Officer Joseph B. Mathews was called out to break up a fight between two men at a resort outside the city of Napa. After arresting the two suspects and booking them in the country jail, Mathews returned to the CHP office where he suffered a cerebral hemorrhage. The 32-year-old patrol officer was a native of Napa and had been a member of the CHP for nine years.

Officer Gardell was struck by a car while in pursuit of a traffic violator on July 11, 1939. He was hospitalized, developed pneumonia and died July 21, 1939.

Officer Fred J. Kowolowski was rounding a sharp bend on a rural road in Santa Clara County when his motorcycle collided with an automobile. The 17-year-old driver of the other vehicle said he had turned from a side road and, seeing the motorcycle coming, stopped. The 29-year-old patrol officer died only hours later. Kowolowski was a former deputy sheriff in Modoc county before he joined the Patrol in 1937.

Captain E. L. Shryver was directing traffic on U.S. Highway 101 in Sonoma County when he was struck by a vehicle and thrown under the trailer it was pulling. Shryver, 46, battled his injuries for two months before he succumbed. A veteran motorcycle officer with 13 years experience, he had recently qualified as district inspector and was first on the promotional list. Shryver was also an expert pistol shot and represented the CHP at several national pistol matches.