In a separate development, police recently travelled to Canada to interview Andy Burnett who was the landlord of a pub across the road from Mr Wilson’s home where his wife, Veronica, ran for help immediately after the shooting.
Mr Burnett was a friend of Mr Wilson’s and is seen as a key witness who is helping police with their investigation.
Detective Superintendent Graeme Mackie, of Police Scotland’s major investigation team, said officers were seeking the public’s help in identifying the two men who were seen on the beach.
“We are following up this new information and I would ask anyone with information, or who may be able to identify the men, to please come forward and speak with us,” he said.
‘Time is no barrier to justice’
“This potential sighting was passed to officers following recent publicity around the case and I am grateful for the positive response we have received from the local community.
“As I have said recently, time is no barrier to justice. More than 17 years have passed since Alistair’s murder, but Police Scotland is committed to bringing his killer to justice and providing the family with the answers they deserve.”
Following a recent review of witness accounts, further analysis of timings from the night in question and “investigative developments”, officers have also altered the description of the man they want to trace in connection with the murder.
Detectives believe the man who shot Alistair on his doorstep to have been aged between 20 and 40 years old at the time. This would mean he is now aged in his mid-30s to almost 60 years old.
He was approximately 5ft 7in tall and was wearing a baseball cap and jacket. Previous appeals described the gunman as being between 30 and 40 years old.