Investigators are trying to determine what caused the crash that killed an eastern Nebraska couple on their way to celebrate their 50th wedding anniversary.

The Lincoln Journal Star reports that Harold and Connie Wheeler of Tamora died Saturday afternoon after their car crossed the centerline and collided with a pickup truck.

Police Capt. Danny Reitan says investigators are looking into whether 76-year-old Harold Wheeler had a medical problem before the crash. Connie Wheeler was 71.

Both Wheelers died at the scene. The truck’s driver suffered only minor injuries.

The Wheelers were on their way to their son’s home in Lincoln where friends and family had gathered to celebrate their anniversary.

Friend Emily Greguras says the Wheelers were a nice couple who loved their dogs and cared about senior issues.