THE voice was that of a little boy. "I wasn't there." "It wasn't me." "John did it." He could have been talking about a smashed window, a shattered piece of glass broken by a ball, and his confession was interspersed with sobs. But ten-year-old Robert Thompson was talking about the most serious crime on the statute book - murder. And he and his partner in crime, Jon Venables, have been incarcerated for the past eight years as a result.

The time has flown and done little to heal the hurt of a family blighted by the killing of two-year-old James Bulger, nor the community torn apart by the unthinkable act.

Now, the killers are to be freed, released by a system anxious not to institutionalise them further. But the release is fraught with difficulties.

Society has been burdened with the task of protection and will have to pay dearly - an estimated £1.5m. Both teenagers will be on licence for the rest of their lives and, as such, will have to be monitored by the authorities. But the case is steeped in so much passion, hatred and vitriol, that their slim chance of surviving in a world which despises them, is through anonymity.

Thousands of pounds have already been spent on creating new identities for Venables and Thompson. They will have new social security numbers, bank accounts, identity cards and even birth certificates. New identities may also have to be created for close family members. The boys may even end up abroad.

Keeping their real names secret once they are back in society will create unique problems for police and probation officers, and some fear the whole enterprise could put the public at risk. The pair used false names while serving their sentences in local authority secure accommodation, and were reportedly moved around to different units to stop anyone guessing their true identities.

Terms of the licence will require their probation officers to keep a close eye on them. But probation service officials believe this will be difficult if officers do not know the true background of their crimes. "The chances of this whole thing falling apart are very high," says Harry Fletcher of the probation officers' union Napo. "You cannot expect a probation officer to supervise Venables or Thompson thinking they are someone else. It would be ludicrous. He would have to be highly trained to spot any deviation in their characters because the worst thing that could happen is that they kill again."

Both boys shocked the world with the motiveless killing of James. They had been little terrors, but were unlikely killers. The family of the victim questions whether the special treatment they have received in a secure children's unit would have been any punishment at all. And only the boys and their carers know whether any treatment has been effective, whether any remorse is shown, whether they are likely to offend again.

"And if the probation officer is privy to their real history, what if one of them starts a relationship with a girl?" Mr Fletcher says. "Does the officer step in and tell the girl who her boyfriend really is? What if Venables or Thompson get picked up by the police or admitted to hospital, and the police do a criminal records check on him? Will the file be flagged so that if someone makes an inquiry about one of them under their new identities, the Home Office will be alerted? If they get into trouble again under the new names, how does the person dealing with them know who they really are?

''There will have to be a significant number of people who will have to know their identities, and it will almost certainly leak out."

And how will the boys cope with the pressure, living a false life haunted by the memory of what they did? How bright are they anyway? It needs a shrewd mind to maintain any form of pretence. What happens when they are intoxicated, what home truths will find their way out under the influence of drink? And how well will they cope with the prospect of being found out, with a life of looking over their shoulders and of the constant physical threat of vigilante attack?

There will be temptation from all quarters. The urge to unburden themselves with new-found friends and confidantes, or to accept "30 pieces of silver", betraying one another to the media or the mob.

The Home Office does not have the power to allow Venables and Thompson to be released without being on a supervision order, adds Mr Fletcher. "It is not going to be easy. It is fraught with difficulties."

But while the obstacles are formidable, they are not insurmountable. Mary Bell joined the country's hall of infamy in 1968 when she was convicted of taking two lives. A life sentence in jail meant 12 years for Bell and, for the past 21 years, she has lived in anonymity, bearing a child who will be 18 this year. Her case will be reviewed then, the courts deciding whether or not the family should be allowed to enjoy living behind a cloak of secrecy.

In all that time, her family and friends, her neighbours and colleagues, have been oblivious to her past, a childhood which turned sinister at the age of 11 when, in Newcastle, she choked the life out of four-year-old Martin Brown, and three-year-old Brian House.

The "evil-eyed" Bell never struck again and would have been lost in obscurity had she not reputedly profited from a book about her crime.

"We do the life sentence," says Martin's mother June Richardson, of Low Fell, Gateshead. "They don't say 'you have got life but we don't mean it' like they do to the criminal who gets life but only serves ten years. The victims haven't got a life."

Insult was added to injury when the book was published and Mrs Richardson had to break the news to devastated members of her family who did not know Martin had been murdered - a secret she had kept for more than 20 years.

Meanwhile, Dee Warner, of the pressure group Mothers Against Murder and Aggression, says Thompson and Venables should get no special favours. "They should take their chances on the streets like every other murderer who is released - they don't get cosseted like this," she says.

After all, it wasn't a window they shattered, it was people's lives.