AS twisted Peter Tobin starts his second life sentence, one critical question remains - how did tragic Vicky Hamilton fall into his evil clutches?

Did the teenager ask him for directions or did she let her guard down and accept a lift from him because she was standing at a bus stop on such a cold wintry night?

The snow was so bad on that fateful night 17 years ago there were fears the buses in West Lothian might stop running.

Vicky and her sister Sharon Brown had been trying hard to arrange a lift for the youngster from Bathgate to her home in Redding, near Falkirk. Why jury had to be warned to ignore Net THE Vicky Hamilton trial brought into sharp focus the difficulties faced by the legal system of ensuring a fair trial despite easy access to the internet.

Tobin's defence counsel. Donald Findlay, QC, told trial judge Lord Emslie on the first day of his concern at the volume of online articles that detailed his client's background.

Wikipedia, which devoted a special page to Peter Tobin and referred to him as a killer and rapist, took down the page for the duration of the trial.

But any of the trial jurors could have gone home, clicked on the Google search engine and found dozens of pages filled with gory detail about the past behaviour of the man in the dock.

Media law expert David McKie admitted the growth of the internet created a "potential legal minefield" for internet service providers such as Google.

But he insisted one of the key planks of the Scottish legal system was that lay jurors had to be trusted to take their responsibilities seriously.

Mr McKie, of Glasgow-based law firm Levy & McRae, said: "Ten years ago, before the internet, jurors could go to the Mitchell Library and dig up background on an accused person.

"That was far more cumbersome and time-consuming than simply pressing a button, but the law is quite clear on contempt of court.

"If we are to accept that jurors look up internet sites after being warned to concentrate solely on the evidence by a judge, that would pre-suppose that they are not responsible jurors and we would go down the slippery slope of not trusting jurors.

"In those circumstances, the whole jury system may well be called into question.

"We know jurors do not inhabit a germ-free' environment, but we must trust them to be fair-minded, to listen to the judge and to determine the case solely on the evidence." Detail about Tobin's previous crimes were on the internet.

But they had been unable to contact Vicky's dad Michael - ironically a bus driver.

Sharon, now 37, told the trial how she hugged Vicky for the last time in Hobart Street, Livingston.

Her younger sister had been agonising over how she should change buses in Bathgate. It was an 85p, half-hour journey - but one she never completed.

Vicky's family had been through some difficult times. Her mother Jeanette and father Michael had split up.

Months before she disappeared there were fears she might have been pregnant and she had been given a good talking-to by police over a false rape allegation.

There were suggestions during the trial that she had run away and had dabbled in cannabis.

But the final weekend she spent with her sister in Livingston was a happy one. The girls enjoyed a good gossip, a couple of long lies, a night out at a pub disco, window shopping and searching for a present for their mother's 40th birthday.

Tragically Jeanette Hamilton died in 1993 without knowing what happened to her daughter.

When Vicky's remains were finally unearthed in a garden in Margate, Kent, police knew the killer right away.

The address at Irvine Drive was a former home of Tobin, recently convicted of Angelika Kluk's murder.

Officers searched another of his former homes in Robertson Avenue, Bathgate, and found a knife in the loft.

But the crucial breakthrough was the discovery of his son's DNA on Vicky's purse, which had been discovered in Edinburgh.

It should all have been an open-and-shut case, but top prosecutors, after failing to secure convictions for the World's End murders and the Templeton Woods killing, were taking no chances.

Both cases had depended to a large extent on DNA evidence and this time police and prosecutors were meticulous in their preparation.

The first decade of the search for Vicky had seen 7631 names logged into the police files. There were 3965 statements, 496 related documents and 380 pieces of potential evidence.

The investigation, still officially a missing person inquiry in spite of police suspicions, was kick-started again in 2006.

Before the results of Operation Mahogany came to court, detectives had trawled through housing department archives, nursery school registers and even managed to pin down one man's visit to Tobin's home from his tax records.

The list of possible witnesses ran to more than 250 names and 111 of them were asked to give evidence - 21 of them on one day alone.

Residents of the Robertson Avenue address came to court just to say they had never seen the knife in the loft. Vicky's bedroom - like any typical teenage girl's - was covered in posters The chip shop Vicky visited on the night she vanished Vicky's mum Jeanette and sister Sharon. Jeanette died never knowing Vicky's remains had been found in this pit Police remove items from Tobin's Bathgate home as they gather evidence against the killer. The developments sparked a furious reaction from Vicky's dad, Michael, and other locals

Peter Roles, 64, of the Construction Industry Training Board, and former workmate Simon Nottle, 53, testified to Tobin's hole digging skills.

Every small detail helped point an accusing finger.

Tobin said nothing during the trial and no witnesses backed up his claim to have an alibi for the day Vicky disappeared.

His attempts to muddy the waters by claiming police had briefly considered another "suspect" - a heroin addict who spent time in a mental hospital - failed to sway the jury.

The contents of Vicky's vital black purse gave some clues to her tragically short life.

It contained a card for her star sign, Taurus, showing her interest in horoscopes, a letter to her teacher about a dental appointment, a leaflet about going on the pill and a letter to a friend.

There were also two scraps of paper giving an address in London.

They were never explained to the trial.