By Mario Cacciottolo
Peter Tobin is said to have boasted of many more victims
Peter Tobin, who has been convicted of the murder of teenager Dinah McNicol, was already serving sentences for the murders of two women.
Police are now restarting Operation Anagram, tracing Tobin's past movements and examining whether he is responsible for any other unsolved crimes.
"I strongly, strongly suspected and formed the theory that Tobin may have indeed been a serial killer."
These were the words of Detective Superintendent David Swindle, who led the Angelika Kluk murder inquiry in 2006, the first for which Tobin was convicted.
"The fact of his age and the method of [Angelika's] killing, and all the other factors surrounding Tobin, made us think this guy's done this before.
"It was also while interviewing relatives of Tobin, that we got indications that Tobin may have been involved in other crimes," he said.
After the case, Det Supt Swindle set up Operation Anagram. It led to the discovery of the bodies of 15-year-old Vicky Hamilton and 18-year-old Dinah McNicol - who had both disappeared in 1991.
Tobin has been convicted of both their murders.
We owe it to the families of the victims and the police will continue to see if we can link Tobin to other outstanding crimes or missing persons
Det Supt David Swindle
Now Tobin has been found guilty of Dinah's murder, police are restarting the operation.
The investigation will reach back to the 1960s and is no easy task - police say there are 1,400 "actions" to be undertaken nationally, to help with the inquiry.
Aside from the length of time involved and the fact 63-year-old Tobin moved frequently, he is also thought to have used up to 40 aliases.
Tobin is alleged to have claimed 48 victims in prison boasts and police are looking at the possibility that he might be "Bible John", the man thought to be responsible for the deaths of three women in Glasgow in the late 1960s.
His conviction of the rape and killing of 23-year-old Angelika Kluk in 2006 led police to understand what kind of a man they were dealing with.
Angelika, a student from Poland, had been working as a cleaner at St Patrick's Roman Catholic Church in Anderston, Glasgow.
Tobin had carried out voluntary work there as a handyman, under a false name, calling himself Pat McLaughlin.
Angelika's body, discovered bound and gagged beneath the floor of St Patrick's Church, was found to have suffered severe head injuries and multiple stab wounds.
Tobin was sentenced to a minimum of 21 years in jail for the murder.
After Tobin's conviction, Operation Anagram helped link him to one of Scotland's biggest missing-persons' inquiries.
Schoolgirl Vicky Hamilton, 15, who lived in Redding near Falkirk had gone missing in Bathgate, West Lothian in 1991.
Police discovered that Tobin had been living in the same area at the same time. When they searched his former home they found evidence, including a dagger, with Vicky's DNA still on it.
From Bathgate Tobin had moved again, this time to Kent. That information proved crucial to a separate cold case review, which re-examined the disappearance of 18-year-old Dinah McNicol.
As a result, in November 2007, officers began a detailed forensic search of his house and back garden in Margate. Specialist equipment including ground-penetrating radar was brought in.
Within days of starting excavations, police discovered Vicky Hamilton's body. In 2008, Tobin was convicted of abducting, raping and killing her and given a life sentence.
In the same garden, they discovered the body of Dinah McNicol, from Tillingham, Essex.
On 3 August 1991 she went to a music festival in Liphook, Hampshire, and on her way home she and a friend hitched a lift.
But when her friend was dropped off along the way, Dinah was left alone with the driver. Her family never heard from her again.
Tobin's fingerprints were found on bin bags used to wrap Dinah's body, and post-mortem examinations showed traces of the drug amitriptyline.
Tobin had used the same drug when he had attacked two teenage girls in Hampshire in 1993, and when he had murdered Vicky Hamilton.
During the Dinah trial, a former neighbour told the court he had seen Tobin digging a hole in the back garden of his home in Margate, Kent, in 1991, which Tobin claimed was a sandpit for his young son.
Tobin's life has been marked by violence and sexual offences.
His first wife Margaret said she was raped three or four times and stabbed by Tobin, then left for dead but rescued by a neighbour who saw blood coming through the ceiling.
In 2005, 24-year-old Cheryl McLachlan said Tobin attacked her with a knife in his flat in Paisley.
"I looked down the side of the seat and there was a belt and a tie, I thought he was going to tie me up," she said.
As part of the reopening of Operation Anagram, police are understood to be re-examining the murders of three women; Patricia Docker, Jemima McDonald and Helen Puttock, all believed to have been killed by "Bible John."
Also under scrutiny are the murders of Jessie Earl, who disappeared from Eastbourne in East Sussex in 1980 and was found dead nine years later, and Louise Kay who disappeared aged 18 from Eastbourne in 1988 and who has never been found.
Police want to trace the owners of jewellery found in Tobin's possession
Assistant Chief Constable Robin Merrett of Sussex Police, who is co-ordinating Operation Anagram, said there are currently no plans to search any premises, but this will be reconsidered should "intelligence and evidence" warrant it.
Police have released pictures of women's jewellery, including pendants, necklaces and brooches, that were in Tobin's possession in 1991 and 2006.
They are appealing for information and are looking for the items' owners.
Det Supt Swindle said the police would keep probing Tobin's past.
"We owe it to the families of the victims, and the police will continue to see if we can link Tobin to other outstanding crimes or missing persons."