Officers have been conducting a full scientific examination of part of Monkland Canal in an effort to find the remains of 11-year-old Moira Anderson.
She left her grandmother's house in Coatbridge on 23 February 1957 to go to the shops but she never returned.
Police divers are expected to begin searching the canal on Monday.
A specialist search team began the first phase of the search of the canal earlier this week.
The operation focused on a 170m (185 yards) stretch of canal at Carnbroe. Although it is 3.5m (11.5ft) deep, around 2m (6.5ft) of that is silt.
The team were joined by leading experts including soil forensic expert Professor Lorna Dawson and forensic anthropologist Prof Sue Black.
Geoforensics expert Prof Alastair Ruffell, as well as a national search advisor from the National Crime Agency and representatives of the Home Office's applied sciences and technology department have also worked on the operation.
The search involved the use of ground penetrating radar, sonar scanning and magnetometry, which identifies magnetic anomalies within the water and silt layer of the canal.
The force said the techniques resulted in the identification of "five distinct areas of anomalies".
Divers from its marine unit will begin their investigation of those areas on Monday, when they will focus on identifying and removing any relevant items.
Bus driver and convicted paedophile Alexander Gartshore, who died in 2006, is suspected of Moira Anderson's murder.
When she left her grandmother's house during a heavy snowstorm, she boarded a Baxter's bus that was driven by Gartshore.
Later that year, he was jailed for raping a 17-year-old babysitter.
In 1999, convicted child abuser James Gallogley named his former friend Gartshore as Moira's murderer.
Gartshore's own daughter Sandra Brown was convinced he was the killer and campaigned to have him charged.
In 2014 prosecutors took the unusual step of announcing that Gartshore would have faced prosecution for the schoolgirl's murder if he were still alive.
In 1957 a witness reported seeing a tall man carrying a large, heavy sack towards the canal the morning after Moira disappeared but the possible sighting was not followed up.
Police searching a North Lanarkshire canal in a bid to find a schoolgirl who disappeared 60 years ago have identified five "areas of interest".