UPDATE: Police have confirmed the sighting of a man in the Darling Downs area on Sunday was not Ian Collett.
Two girls on horseback reported the sighting to police officers, but a statement today said the search would not continue in the Darling Downs area.
Police and emergency services are continuing to look for Mr Collett in the Bedfordale area.
The forward command post will move from Bedfordale to the Mundijong Police Station today.
Although the last confirmed sighting of Mr Collett was around the Armadale area on Saturday, May 19, police are not discounting the idea that he could be in another area.
EARLIER: THE search for missing man Ian Collett, who has dementia, continues into a sixth day today with police searching areas off Albany Highway south-east of Perth.
The grandfather was last seen around midnight on Saturday walking along the Albany Highway at Mount Cooke, near Jarrahdale.
Police say there’s been no further confirmed sightings.
“Given his age and his illness, there’s a very, very slim chance that he’s still mobile,” WA Police Acting Inspector Darryl Brandis told reporters on Wednesday.
“We’ve had no more new information to say that he has got a lift from a motorist or that he’s found another way to move further south.
“Now we’re focusing ground troops on finding him along the road somewhere.”
All-terrain vehicles have been added to the search effort, which also involves mounted police and SES volunteers on foot.
They are searching up to 10 metres off the road.
“Luckily, he’s got warm clothing … and if he has been able to find shelter, it’s enough for him to still be here with us today,” Acting Inspector Brandis said.
Mr Collett’s wife Deborah was tearful when asking for the public’s help.
“We miss him and we want him back,” she said on Tuesday.
Anyone who thinks they have seen Mr Collett can phone police on 131 444.