The Missouri State Highway Patrol has now released the names of two people killed in a crash Saturday on I-29 at the Bee Creek Bridge near Dearborn, Missouri.

Officials still don’t know what caused 51-year-old Robert Richardson of Kansas City, Kansas to lose control of the Volvo dump truck.

Richardson and his passenger, 35-year-old Crystal Harris of Kansas City, Kansas, were both pronounced dead at the scene.

The truck careened through the guardrail and bridge abutment and down into Bee Creek.