A Doncaster man died in a collision involving his motorbike and a car in Barnsley.
The 49-year-old, who has not yet been named, was involved in a crash on the A61 Upper Sheffield Road, Worsbrough, at 4.25pm yesterday.
A black Land Rover Freelander and a black and grey Moto Guzzi motorcycle collided close to the junction with Knowle Road.
The motorcyclist suffered fatal injuries and was pronounced dead at the scene.
His family have been informed and are receiving support.
A South Yorkshire Police spokeswoman said: "Officers are keen to trace the driver of a white van, believed to have been travelling along the same road shortly prior to the collision, as they believe he may have vital information.
"If you witnessed the collision, or have any information that may be able to assist officers with their enquiries, please report it."
Call South Yorkshire Police on 101 quoting incident number 706 of November 15.