Police are continuing to appeal for public assistance to help them trace Stuart Brown, who is missing from his home in Tarbet.
The 76-year-old was last seen walking along the A83 trunk road between Tarbet and Arrochar around 1pm on Thursday September 28.
Stuart is a keen walker and is known to hitchhike, regularly walking the Three Lochs Way which runs from Tarbet to Arrochar.
He is described as around 5ft 8ins in height and of a slim build with short, brown and grey hair which is balding.
He also walks with a slight stoop.
Inspector Karen MacLennan said: “Did you see an elderly gentleman walking or attempting to hitchhike from Tarbet towards Balloch on Thursday? If so, please contact us as soon as possible.
“We would also like to see any dash-cam footage from along the A83 between Tarbet and Arrochar between 12pm and 2pm as well as 5.30pm and 7.30pm.”
Information should be passed to 101 with reference number 1466 of September 29.