One of the killers of James Bulger has been jailed for two years after admitting downloading and distributing indecent images of children.
Jon Venables, now 27, was 10 when he and friend Robert Thompson murdered the toddler in Bootle, Merseyside, in 1993.
Venables was living in Cheshire when the images were found on his computer by a probation officer he had invited to his home, it has emerged.
James's mother Denise Fergus said "justice had not been done".
Her spokesman, Chris Johnson, said the two-year sentence "was simply not enough to meet the gravity of what this person did".
Mr Justice Bean, sitting at the Old Bailey, said Venables had "colluded in the harm of children".
However, the judge said it would be "wrong" for Venables' sentence to be increased because of his previous crime.
But he stressed Venables would not be automatically freed after serving half of his jail term like any other prisoner and it would be for the Parole Board to determine when or if he would be released.
The judge partially lifted reporting restrictions to reveal Venables had been living in Cheshire at the time of the offences and that the case was dealt with by Cheshire police and Cheshire probation service.
Robin Makin, the solicitor for James's father Ralph Bulger, said giving somebody a false identity, as happened to Venables after he was released in 2001, was a "liberal experiment" that was never really going to work.
Speaking outside the Old Bailey, he said: "What appears to have... come out today is that there must have been totally inadequate supervision and support from the probation service."
He also said Mr Bulger was unhappy the judge had not taken into account James's murder when sentencing.
Venables was banned from using a computer or the internet for five years and will be placed on the sex offenders register for 10 years upon any eventual release.
He pleaded guilty to three offences under the 1978 Protection of Children Act. The first involved downloading 57 indecent pictures of children between February 2009 and February 2010.
The second involved distributing three indecent photographs of children in February 2010, while a third involved distributing 42 images in February 2008.
It has also been revealed that Cheshire police had produced a "threat assessment" to try to establish what could happen to Venables were his assumed identity revealed.
That assessment concluded that Venables would face the highest possible risk of being attacked if his new name was either published in the media or known elsewhere in society.
The threat assessment document said "someone could find Venables with the intention of killing him".
Venables and Thompson were released in 2001 with new identities and it was the fear that his had been discovered that led Venables to contact his probation officer.
When the officer arrived, Venables was trying to delete files from his computer and remove the hard drive, prosecutors said.
He was subsequently taken to a police station with the machine where it was examined by officers, they added.
Louis Mably, prosecuting, said eight of the images were at level four, the second most serious category of images of child sex abuse. Two were level three, three were level two, and 44 were level one, the least serious, he added. The images involved children as young as two and some showed the rape of young girls.
Edward Fitzgerald QC, representing Venables, said his murder conviction had cast a long shadow over his life, and he had been living a "wholly abnormal" existence, punctuated by "vilification, demonisation, and threats to his life".
He said his client had held down a job ever since his release, but it had been difficult for him to form relationships with women because it was a condition of his licence that he had to tell anyone he was in a close relationship with his true identity.
Venables was arrested for affray in September 2008 but the charge was dropped. He claimed he had acted in self-defence, but was given a formal warning that his actions had breached the terms of his release.
Mr Fitzgerald said Venables had also become addicted to drugs, including cocaine, and was cautioned for possession in December 2008.
James's mother said after the hearing that she was "surprised and concerned" that Venables had not been recalled to prison following those incidents and called for Justice Secretary Ken Clarke to investigate the actions of the probation service.
The Ministry of Justice said a review would be carried out, but "the direct responsibility for these offences must lie with Jon Venables".
Mr Mably said Venables' computer "indicated the defendant had an extensive history of searching for and downloading indecent images of children using the internet".
In a statement made to police in March, Venables said he considered it "breaking the last taboo", but insisted he had "no intention" of having sex with a young girl.
The court also heard that in online communications Venables claimed to be a 35-year-old married woman called Dawn Smith who abused her eight-year-old daughter, and offered to sell access to the child.
In a statement read to the court, Venables said he was "genuinely ashamed" of the offences.
Venables and Thompson abducted two-year-old James while he was shopping with his mother at the New Strand Shopping Centre in Bootle on 12 February 1993.
The toddler was beaten with bricks and iron bars and his body left on a railway line.
His killers were detained at Her Majesty's pleasure, the usual substitute for life imprisonment for juvenile offenders.
In 2001, when they turned 18, both were freed, despite public outcry.