Two Washington state residents were killed and two others were injured in a motorcycle crash in eastern Montana.

The Montana Highway Patrol says a 57-year-old man and his 55-year-old female passenger were eastbound on U.S. Highway 12 in Rosebud County Tuesday afternoon when they struck a trailer being pulled by a motorcycle in front of them as the driver slowed down to pull over.

The Billings Gazette reports the victims, both from Ephrata, Wash., died at the scene. Their names have not been released.

The 63-year-old driver of the leading motorcycle and his 61-year-old female passenger were taken to the hospital on Forsyth. Both are from Ocean Park, Wash.

The patrol says none of the bikers were wearing helmets.