Cordell, Okla. ? Four members of a Wichita, Kan., family who were visiting southwestern Oklahoma for graduation ceremonies were killed when their car was hit head-on by a vehicle driven by a relative, police said Monday.

Police Chief Lonnie Smith said the four people killed in the Cordell crash were Danny Cecil Sumler, 60; his wife, Brenda Joyce Sumler; their 28-year-old son, Carl; and their 6-year-old grandson, Daniel Sumler.

Smith said Carl Sumler was driving a Kia van north on Oklahoma 183 when it collided with a Nissan sport utility vehicle driven by a female relative from Hobart. She was headed the opposite direction when she crossed the center line.