Police say they remain hopeful of finding the remains of schoolgirl Moira Anderson who disappeared 60 years ago.
On Monday, divers were searching a canal as part of investigations into the disappearance and are expected to retrieve "objects" for assessment by forensics.
Moira was 11-years-old when she disappeared after leaving her grandmother's home to go to the shop for groceries 60 years ago.
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Her disappearance remains one of Scotland's longest-running criminal mysteries.
But following a full scientific examination of a site in Carnbroe, North Lanarkshire, police confirmed five areas of interest have been identified.
And a "recovery phase" within the parameters of Monkland Canal is now underway.
Police divers, led by Superintendent Pat Campbell, are sifting through 2.5metres of silt at designated points where an initial search using earth science techniques discovered anomalies at the bottom of the canal.
Teams of four divers are searching at a time in a small orange boat in a bid to recover large buckets of silt which will then be examined by forensic experts.
Speaking as the search entered its sixth day, Superintendent Campbell detailed what they are hoping to achieve.
He said: "There are five distinct areas which have been identified for us.
"They relate to items or structures within the silt layer which we are now going to deploy divers into the water to remove these objects.
"They have been highlighted to us by some of the specialist scans on the waterway.
"From now until Thursday we will be under water.
"We have specialists from the University of Dundee who specialise in the identification of bone and bone structures, so anything which is removed from the canal of any concern, they will be able to identify whether it is human or otherwise."
Photo credit: Jamie Simpson
While remaining cautious on what could be found, Superintendent Campbell said he believed there will be bone fragment found.
He said: "We will be able to recover what the anomalies are and we are very confident that we will be able to remove the items.
"Any bones that we do recover, we have the specialists on site to determine whether they are canine or human.
"If they are human, it will be a slow process to identify them."
The family of Moira declined to be present at the site of the search but do remain hopeful that their 60 years of agony will finally come to a conclusion soon.
Superintendent Campbell said: "Moira's two sisters have been fully updated on what we are doing here.
"They are realistic on the chances of finding anything but they have been very supportive of us.
"They are extremely hopeful that we can bring this to a successful end."
On the day of Moira's disappearance, she was spotted getting on a bus driven by convicted paedophile Alexander Gartshore.
Photo credit: Jamie Simpson
In 1957, a witness then reported seeing a tall man - whose description matched Gartshore's appearance - carrying a large bag the day after Moira disappeared, although police failed to follow this up at the time.
He died aged 85 in 2006 and was never charged with the disappearance of Moira.
However, in 2014, Lord Advocate, Frank Mulholland QC named Gartshore as the likely killer of Moira as there is sufficient credible and reliable evidence.
Superintendent Campbell ruled out the possibility of the disappearance being linked to a larger paedophile network.
He said: "We have absolutely nothing to indicate that theory."