POLICE say they will act on any new information in the search for a missing 90-year-old as efforts to trace him are scaled back after a six-month operation.

William Ritchie, known as Bill, was reported missing on January 14 when neighbours noticed he had not gone about his usual routine of walking around Fraserburgh.

A major search operation was launched involving Police Scotland's helicopter, dog and diving units but no trace was found.

The last verified sighting on CCTV was taken from Asda on December 21 last year but a number of people told officers they saw Mr Ritchie in and around the town in the days leading up to him being reported missing.

In the last six months the search team has reviewed key areas including the shore and rural routes.

Mr Ritchie is around 5ft 7in with a slim build and short grey hair.

It is not known what he was wearing when he went missing, however he would usually wear a long black jacket and a flat cap.

Detective Inspector Stewart Drummond said leads have been exhausted but that officers will act on any new information.

"To maximise the use of our resources and time in any missing person inquiry we have focused our searches in areas led by the information and intelligence we have had available to us," Mr Drummond said.

"Once our leads are exhausted it becomes impossible to know where to search next and inevitably our efforts have now been scaled back.

"Please be assured that we will continue to act on any new information that we receive and that the inquiry surrounding a missing person is never closed.

"It is not too late to get in touch with information if you think it could help and I would encourage you to get in touch by contacting Police on 101 quoting incident no. 2549 of Jan 14."

He added: "I know that those who know Bill or even just recognise him to say hello have been anxious to know where he went, and it is extremely frustrating for us all not knowing exactly what has happened to him.

"We do know there were sightings of him in Fraserburgh in early January and our enquiries indicate that he was possibly unwell in the weeks leading up to his disappearance.

"His usual routine changed and he was described as looking frail and not as fit and agile as normal. Despite this he seems to have continued with his regular walks around the town, the shoreline and on rural routes.

"I would like to thank everyone who has provided information so far to assist with our searches and to those who have shared our appeals for information. As is always the case with inquiries of this nature, the information and support we receive from the public is crucial and always appreciated."