Colin has been missing from his home in Dewsbury since Sunday, November 17.
CCTV released shows him at 5.30am on Sunday morning in Owl Road, Shaw Cross, Dewsbury area.
He was later spotted on CCTV walking on Leeds Road toward the ring road at 5.53am.
There have been no confirmed sightings since then and search teams are still checking Shaw Cross in an effort to find him.
An extensive search operation has been running throughout the week but officers have been unable to locate him.
Officers are very concerned for his welfare due to the recent freezing cold temperatures.
He is thought to be wearing a blue blue fleece, grey pyjama bottoms and a dark coloured beanie hat.
Detective Inspector Stephanie Fox of Kirklees CID, said: “We desperately need to find Colin and reunite him with his family. There is an extensive search operation in place and I am again appealing directly to anyone who sees Colin or thinks they might have seen him to get in contact
“He is an elderly gentleman wearing clothes that are unsuitable for the harsh conditions.
“We have had a lot of people who want to help find Colin and would like to thank the community for their help.
“Any small amount of information could really help us and our specialist teams currently out looking for him.”
Officers are also appealing for anyone who was in the area of Owl Lane, Shaw Cross Dewsbury at or around 0530am on Sunday and may have seen Colin, in particular any drivers who may have dash cam footage to get in contact.
Anyone with information or anyone who believes they may have seen Colin is asked to contact police on 101 999, quoting log 1104 of 17/11.