Senior detectives are convinced serial killer Peter Tobin is responsible for some of the country's most notorious unsolved murders.
Members of at least eight forces have spent years carefully reconstructing his movements under a series of aliases.
Police launched a huge operation, codenamed Anagram, in a bid to to rule Tobin in or out of a large number of unresolved inquiries.
They alerted colleagues across the country that he could be behind other crimes against vulnerable women since he left his home town of Johnstone, Renfrewshire.
One senior officer said Tobin's offences were "horrific" and added that "without doubt he has probably committed more".
Although Tobin will die in jail, police said they owed it to his victims to get to the bottom of his crimes.
They are believed to have narrowed their inquiries to nine unsolved cases of women who have been murdered or have disappeared.
Only last week a television appeal led to a flood of fresh information after a woman said Tobin drugged and attacked her in Glasgow in 1968.
Tobin, 63, lived in several towns and cities, including Glasgow, Brighton, East Sussex, Margate, Kent, and Havant, Hampshire.
The three-times married father of two worked in a variety of jobs, hung out with biker gangs and used prostitutes.
He also owned a huge number of cars, as many as 120, which investigators believe he may have used to trawl the motorways for hitch-hikers.
One intriguing and chilling clue was the discovery of a treasure trove of women's jewellery kept at his home.
Police feared the items, like pendants, brooches and necklace clasps, could have been sick keepsakes of his crimes.
Cases that have been linked to the inquiry included:
* The murders of three women in Glasgow in 1968 and 1969 - thought to have been victims of a mysterious figure nicknamed "Bible John".
All three women were brunettes and all were wearing black dresses. They were savagely assaulted and murdered after being picked up at the city's Barrowlands dance hall.
Patricia Docker, 25, was killed in February 1968; Jemima McDonald, 32, was strangled in August 1969 and Helen Puttock, 29, was murdered in October 1969.
The killer earned his nickname after a taxi driver, who drove the murderer with his last victim, remembered him quoting the Bible.
Tobin, who had links with the church throughout his life, was living in the city around this time. He would have been in his early 20s.
* Schoolgirls Karen Hadaway, 10, and Nicola Fellows, nine, were found strangled in Wild Park, Brighton, in October 1986. The cases became known as the Babes in the Woods killings.
Labourer Russell Bishop was charged with the murders but was acquitted after the prosecution admitted a series of errors in the presentation of forensic evidence at his trial at Lewes Crown Court in 1987.
Bishop, from Brighton, was jailed for life in 1991 for kidnapping and sexually assaulting a seven-year-old girl from Brighton but has always denied killing Karen and Nicola.
Tobin lived in Brighton for 20 years from the late 1960s, including in an eight-bedroom house with a patio garden in Dyke Road.
* Art student Jessie Earl, 22, who disappeared from a bedsit in Eastbourne, East Sussex, in May 1980.
Her partially-decomposed remains were found on a cliff near Beachy Head in 1989 by kite-flyers. Police stepped up a murder inquiry in 2000.
Earlier this year, Miss Earl's family said they were desperate to find out if Tobin was responsible.
* Patsy Morris disappeared in London in 1980 aged 14.
The teenager's body was discovered hidden in undergrowth on Hounslow Heath, south-west London, in mid-summer.
Her father George said he believed his daughter could be one of Tobin's victims.
"As soon as I read about the other girl's body being found in Tobin's backyard, something inside me clicked," said Mr Morris.
* Another victim could be Louise Kay, 18, who disappeared in Eastbourne in 1989. Her body has never been found. Tobin was working in a nearby hotel at the time.
* Other potential victims are law student Pamela Exall, 22, who vanished in 1974 while holidaying in Norfolk; schoolgirl Patricia Morris, 14, who went missing in Essex in 1980 and Suzanne Lawrence, 14, last seen in Essex in July 1979.
* Police also investigated if Tobin had any links to the death of 19-year-old Lorraine Jacob in Liverpool in September 1970.
But in February 2008 they said Harvey Richardson, 77, left a hand-written confession to the crime before his death.Reuse content