Police have opened an investigation after a picture of Jon Venables, one of toddler James Bulger's killers, was published on Twitter.
The image was retweeted hundreds of times by users, flouting a court ban on material which could identify the 30-year-old.
The banned image showed two images of Venables at the time of his arrest for the 1993 side-by-side with two images of a man who is reportedly Venables today.
Twitter users threatened Venables, some of them demanding that he be lynched when he is released from prison.
The Attorney General's Office refused to say whether the newly tweeted image was Venables or not. It is also unknown which police force is investigating the image.
Those who published it risk being found guilty of contempt of court, a serious common law offence which carries the possibility of a prison sentence or steep fines.
An Attorney General spokesman said: "The Attorney General's Office has been alerted to a possible contempt of court. We are liaising with the Ministry of Justice and others to establish the facts.
"We can neither confirm nor deny whether the pictures in question are of Jon Venables.
"It should be noted, there is a worldwide injunction in place which prevents the publication of any images or information purporting to identify anyone as Jon Venables."
The image of Venables surfaced within days of the 20th anniversary of James Bulger's death.
Venables and accomplice Robert Thompson were released from prison in 2001, eight years after being convicted for killing the toddler after abducting him from the Strand shopping centre in Liverpool.
Venables' parole was revoked in 2010 for downloading and distributing images of children. He was recalled to prison after reportedly blowing his own cover by revealing who he was, despite receiving a new identity from authorities.
The lawyer who first represented Venables following his arrest for killing James, spoke recently of his disbelief that he was capable of the killing.
Laurence Lee told the Dail Mail: "He was like an angelic-looking eight-year-old. I thought, 'What am I doing here? He couldn't be capable of anything like this.
"He was so convincing in his first interview that he had been nowhere near the Strand. I believed him."