Police believe mechanics and car garages in North Yorkshire may be able to help with an investigation into a hit and run near Selby.
A car and a motorbike were involved in a crash on Sunday but the car driver didn't stop and fled the scene.
North Yorkshire Police say the silver saloon, which was possibly a VW or a Skoda, suffered severe rear bumper damage as a result of the collision and are asking businesses that might have repaired a silver car in the last week to come forward.
The crash happened at around 4.40pm on Sunday as a motorcyclist was travelling along the B1222 near Peckfield, Sherburn in Elmet. The bike and the car were involved in a collision at the junction with the A63.
The motorcyclist, a man in his 20s, received serious injuries which required hospital treatment but has since been released.
Officers are keen to speak with anyone who either witnessed the collision or who believes they may know the vehicle involved to contact them with information.
If you wish to provide information anonymously then this can be done by contacting the independent charity Crimestoppers on 0800 555 111.