Police are looking to trace a mystery witness who walked past a dying grandfather moments after he was hit by a car on New Year's Day.

John Ogston died after he was found critically injured on Dundee's Mains Road, close to its junction with Bayne Square.

Police say he had suffered crush injuries after being struck by a mystery vehicle around 11pm.

Now officers have revealed a man was captured on CCTV walking down Mains Road past where the father-of-two lay with "catastrophic injuries".

Mr Ogston, 67, who had been drinking in the nearby Bowbridge Bar before making his way towards his daughter's home in Bayne Square when the incident occurred.

Police say the grandfather, who retired from working at DC Thomson's Kingsway printing plant seven years ago, fell and injured himself half way down the road and was assisted back to his feet by a woman and a passing taxi driver.

The woman helped Mr Ogston further down the road and then went on ahead of him to summon assistance from his daughter, who lived around 100 yards further down the road.

At some point in the moments that followed Mr Ogston is understood to have fallen onto the road and been run over by a car.

The vehicle then drove off.

Detective Chief Inspector Iain Wales, the officer leading the inquiry, revealed he is keen to speak to one witness.

He said: "There is one person we have seen on CCTV who walked down Mains Road on the pavement who must have walked past John, probably just after the collision with the car.

"There is nothing to suggest that person is involved but that person is key to our enquiry.

"If you were walking down Mains Road around 11.10pm on New Years Night you may have vital information."

He also issued a direct appeal to the driver.

Detective Chief Inspector Wales said: "If it was you who was driving that car and this was an accident please come forward.

"Tell us now what has happened.

"Similarly, if a friend, associate or loved one has come home and confessed to being involved in an accident and you think this may be it please come forward."

The senior officer said the uncertainty surrounding the case is compounding the family's misery.

He added: "Unfortunately we don't know what happened to John.

"We do know he has been involved in a collision with that vehicle but we have not identified that vehicle or the driver as yet.

"Understandably his family are really struggling to come to terms with this because they don't know what has happened to their dad.

"We are working tirelessly to find an answer for the family.

"If you know what has happened to John please, please come forward for the sake of the family."