A motorcyclist killed in a crash on an Aberdeenshire road has been named by police.

John Alexander, 47, from Kintore, died on the A93 Banchory to Aboyne road, near Kincardine O'Neil, on Sunday around 4.30pm, after colliding with a car.

Grampian Police said that a substance on the road, thought to be oil or diesel, may have contributed to the accident.

Mr Alexander, who ran a roofing business, died when his Yamaha motorcycle collided with a Nissan Qashqai being driven by a 49-year-old woman.

The car driver and her two woman passengers were treated at Aberdeen Royal Infirmary following the crash.

The road was closed for five hours while police examined the scene.

The family of Mr Alexander, who was a member of Grampian Motorcycle Club, paid tribute to him.

They said: "John was a hard working family man who loved his wife and children.

"He ran a local roofing business and enjoyed being out on his bike – he was also an active a member of the Grampian Motorcycle Club.

"I would like to thank everyone who has been in touch and offered so much help."

Roads policing inspector Ian Kirkwood said: "We are following a number of lines of inquiry however on our arrival at the scene yesterday, we found the carriageway contaminated with some sort of oil, possibly diesel and this may have been a contributory factor. 

"This substance has been submitted for analysis and we await the results but it is important that we narrow down the times when the road surface became contaminated.

"I would ask for any motorists who travelled on the A93 between the Banchory and Ballater areas to get in touch if they either saw a vehicle leaking diesel or other substance on the road, if they saw the contamination on the road or indeed if they travelled that road and there was no contamination.

"This will assist us working out an approximate time frame when the contamination occurred."

Anyone with information can contact police by phoning 08456 005700.