Peter Tobin was one of Britain’s most hated serial killers – and the full extent of his violence may never be known.

The murderer, rapist and paedophile was said to have been in “total denial” about his crimes and never admitted his guilt for the sordid killings he carried out.

Serving life for the murders of Angelika Kluk, Vicky Hamilton and Dinah McNicol, he was certain to die behind bars but detectives never completely shut the door on their efforts to link him to other crimes.

Vast police hours were spent in recent years piecing together the loner’s nomadic lifestyle on the fringes of society, where he hid behind a variety of identities.

Officers believe Tobin will have killed others and had at least 40 aliases and 150 cars during his life to hide his tracks as he targeted vulnerable women.

Born in August 1946 in Johnstone, Renfrewshire, Tobin’s life of crime began after he was sent to a reform school at the age of seven.

In his teens and early twenties he served jail terms for burglary, forgery and conspiracy.

In 1994 he was jailed for 14 years for a sickening double sex attack on two schoolgirls.

Tobin had plied the teenagers with a cocktail of drugs and alcohol at his flat in Havant, Hampshire, before abusing them.

He went on the run but was found after hiding in a Christian drop-in centre in Coventry under a false name.

Tobin was also a serial wife beater, with all three of his former spouses claiming he repeatedly and viciously attacked them.

But it was only with the murder and rape of Polish student Angelika Kluk in 2006 that Tobin’s double life really began to unravel.

The odd-job man had been released from prison, after the attack on two young girls, in 2004 and moved to a flat in Paisley’s Brown Street.

The registered sex offender went on the run for nearly a year before killing Miss Kluk.

Tobin – who was using the false name of Pat McLaughlin – stabbed and gagged the 23-year-old Polish student in September 2006 before hiding her remains beneath the floorboards of a Glasgow church.

He was jailed for at least 21 years in May 2007 following his first murder trial at the High Court in Edinburgh.

It was the police team investigating the student’s murder who first noticed that Tobin had been living in Bathgate at the time 15-year-old Vicky Hamilton vanished in 1991.

Veteran cold case detectives scented a fresh lead. With Tobin firmly in their sights, officers searched the former properties where the drifter had lived over the years.

The body of Vicky – Tobin’s first known murder victim – and that of 18-year-old Dinah McNicol were unearthed 17 years after the girls disappeared, buried in the garden of Tobin’s former home in Margate, Kent.

He had abducted Vicky in Bathgate, West Lothian, on the evening of February 10 1991, while she waited for a bus. He drugged her, strangled her, carried out a serious sex attack and murdered her.

Tobin received a life sentence with a minimum term of 30 years for Ms Hamilton’s killing after a trial at the High Court in Dundee at the end of 2008.

A year later, he was convicted of a third murder.

Miss McNicol was the second young woman Tobin murdered in 1991.

She vanished in August that year while hitchhiking to her home in Tillingham, Essex, after leaving a music festival. She too had been drugged and strangled.

Tobin was ordered to spend the rest of his life behind bars after a three-day trial at Chelmsford Crown Court.

But it is widely suspected that Tobin’s violence went further and that he was behind other killings.

Police examined hundreds of other unsolved murder and missing persons cases to see if they could be linked to the serial killer.

Their operation, codenamed Anagram, was launched in 2006 and wound down in 2011.

Cases detectives are thought to have examined include the mysterious Bible John murders in Glasgow between 1968 and 1969. Three women, Patricia Docker, 25, Jemima McDonald, 32 and Helen Puttock, 29, were all murdered.

Other cases may include the murders of art student Jessie Earl, 22, who disappeared from a bedsit in Eastbourne, East Sussex, in May 1980, and Louise Kay, 18, whose body was never found after she vanished following a night-out in Eastbourne in 1988.

There are several other possible cases, including law student Pamela Exall, 22, who vanished in Norfolk in 1974 and schoolgirl Patricia Morris, 14, who went missing in Essex in 1980.

Detectives scaled down Operation Anagram in 2011 but stressed it would never end.

Speaking at the time, Detective Superintendent David Swindle, of the then Strathclyde Police, who led the operation, voiced hope that Tobin would give up his secrets before he died in prison.

But the killer has now taken those secrets with him to the grave.

Mr Swindle said: “Peter Tobin is totally evil. He has absolutely no respect for human life.”