The family of a missing 88-year-old woman deserve a "thorough and timely investigation", Scotland's Justice Secretary has said, after it emerged that a possible sighting of the pensioner was not followed up by police officers.
A body believed to be that of Janet McKay, who suffered from dementia, was discovered in Clydebank yesterday, nine days after she was seen leaving her home in the Knightswood area of Glasgow.
The last reported sighting of her had been on CCTV leaving a bus in Clydebank on the day she went missing.
But Chief Superintendent Andy Bates, of Police Scotland, has now confirmed that a member of the public informed police last Friday of a possible sighting of Ms McKay, but that the information was not passed to call handling centres or to the inquiry team.
Officers have apologised to Ms McKay's family and the issue has been referred to the Police Investigations and Review Commissioner (PIRC).
Justice Secretary Michael Matheson, told BBC Radio Scotland the death was a tragedy for her family and friends, as he offered them his condolences.
He told the Good Morning Scotland programme: "What's now important though is that we establish all of the facts relating to this particular matter.
"The Lord Advocate has immediately referred the matter to the Police Investigations and Review Commissioner (PIRC), as have Police Scotland, who will now be responsible for investigating the way in which Police Scotland have handled this particular missing persons inquiry.
"It's important that we allow them to undertake that investigation, which will be directed by the Lord Advocate, who will ensure that there is a very thorough and timely investigation into this matter because that's what the family deserve at the very least in order to get answers to how they conducted this particular inquiry."
The latest incident follows a review of Police Scotland's procedures launched after the deaths of John Yuill and Lamara Bell, who lay undiscovered for days despite a sighting of their crashed car off the M9 being reported to a police control room.
Mr Matheson said police have been clear to point out that the latest case does not relate to information passed to a call centre.
"They are clear that this is information that wasn't actually passed to a call centre in the first place and then when it eventually was passed to the call centre it was then actioned immediately to the investigation team," he told the programme.
"I think it's important we allow the investigation by the Police Investigation and Review Commission to be taken forward and we shouldn't prejudice that by trying to pre-empt any of the matters around this particular incident."
In a statement issued through the force last night, Mr Bates said: "On Friday evening as part of our inquiries, a member of the public provided us with information of a possible sighting of the missing person. This information was not passed to the call handling centres nor was it passed to the inquiry team.
"On Tuesday further information about this potential sighting was received through the call handling centre who immediately passed it to the inquiry team. Following further extensive inquiry a body was discovered. We have kept Janet's family fully informed.
"I would like to apologise to the family for any distress caused at this difficult time and take this opportunity to express my condolences to the family and friends and thank those members of the public who supported the search for Janet.
"This incident has now been referred by Police Scotland and the Crown Office and Procurator Fiscal Service to the Police Investigation and Review Commissioner for investigation."
Scottish Liberal Democrat leader Willie Rennie has described the pensioner case as "terribly sad" as he welcomed the PIRC inquiry to establish the full facts.
He told BBC Radio Scotland: "I think it's too early to tell exactly what's happened here.
"What is clear is that they (the police) have apologised and I thank Police Scotland for having done that and being so upfront so early.
"I think the fact the Lord Advocate has instructed a Police Investigations and Review Commissioner inquiry into the case means that we will in due course get the full facts coming out, because that's exactly what we need in order to retain confidence in police and how it's operating."
Mr Rennie said it has been made clear that the police call centres were not involved in this latest case, whereas they were "central to the problem on the M9".
He told Good Morning Scotland: "It's really important that we understand how the information flows throughout Police Scotland so that we are actually reassured that this is a rare error, rather than a system problem."
Chief Constable Sir Stephen House last month announced he would stand down earlier than expected following sustained public and political criticism over call centre failings, and controversies over stop-and-search and armed police patrols.