A man serving a life sentence has admitted to attacking Mark Bridger, who killed five-year-old April Jones last year.
Juvinai Ferreira, 22, pleaded guilty to wounding Bridger when he appeared at Leeds Crown Court via video-link.
Ferreira attacked the 47-year-old in Wakefield Prison just months after Bridger was sentenced to life in jail for abducting and murdering April Jones, five, in Machynlleth, Wales last year.
No details of the attack were given in court today and Ferreira will be sentenced on October 2.
According to reports at the time of the attack, which happened on July 7, Bridger needed hospital treatment to a face wound after he was slashed with a makeshift knife.
He was returned to Wakefield after his injury was stitched.
On screen in court today, Ferreira, who is a convicted murderer and originally from Gambia, looked bored and propped his head up with his hand for most of the proceedings as he sat at a desk in prison clothes.
At one point in the 20-minute hearing he asked one of his guards: "I thought this was going to be quick?"
And, after Judge Christopher Batty told him the case was going to be adjourned, Ferreira said to him: "Can you just not sentence me? I can't keep coming back.
"Just give me anything and move on."
Judge Batty told him he needed a pre-sentence report to assess his level of dangerousness and decide whether a second life term was appropriate.
Ferreira was found guilty at Norwich Crown Court in 2009 of murdering Elaine Walpole in Dereham, Norfolk, in April 2008.
At the time police said Ferreira moved to Dereham in 2007 with a relative after escaping civil war in Africa.
He befriended 47-year-old Miss Walpole, an alcoholic who lived alone, after they met at a shop and she bought him cigarettes.
Prosecutors at the time suggested that Ferreira was ''sex-crazed''.
Post-mortem tests showed that Miss Walpole, a former hotel worker who had three children, had been stabbed three times and bitten.
Detectives and forensic experts spent nearly a year carrying out checks to show Ferreira was an adult as he said he was 16. Once it was proved he was an adult, Ferreira was given a life sentence and told he must serve at least 22 years before being considered for parole.
Father-of-six Bridger snatched April near her home in Machynlleth. He was given a whole-life tariff by a judge in May at Mold Crown Court. The five-year-old's body has never been found.