WICHITA (AP) – Police believe a man might have suffered some type of medical problem before the van he was driving crashed in Wichita, killing him and his wife.

Lt. Joe Schroeder says 56-six-year-old Randall Storms was driving the van Sunday afternoon when it suddenly veered off the street into a drainage ditch and hit a retaining wall. Storms and his 59-year-old wife, Suzy, died at the scene, along with a service dog.

The Wichita Eagle reports that witnesses said the vehicle was driving normally before it drifted to the left just before the crash. Schroeder says speed and a vehicle malfunction weren’t factors in the crash.

The vehicle was modified so Randall Storms, who used a wheelchair, could operate it with his hands.