Police believe two cyclists who passed a crash involving a motorbike and a tractor in which a man died, may hold key information about how it happened.
Colin Rutherford was riding a Harley Davidson on the A77, near Floak Quarry in East Ayrshire on 11 August, when he collided with a John Deer tractor.
The 59-year-old biker from Irvine died at the scene.
Officers are appealing for a female cyclist and another male cyclist, who saw the vehicles, to come forward.
Sgt Cat Gibbons said: "Our inquiries have revealed that there was a female cyclist who spoke with an off-duty doctor about the crash and also a male cyclist who was with a young boy aged around 10-12 years, also on a push bike, who cycled past at the time of the crash.
"I urge these people to come forward and speak to police as soon as possible as they may be able to provide information that will help us establish the exact circumstances of this tragic incident."