Man who tortured Daniel Morcombe’s killer jailed for three years

An inmate who poured boiling water over Daniel Morcombe's killer has been sentenced to three years' jail.

Adam Paul Davidson, 31, pleaded guilty in the Brisbane District Court on Monday to torturing Brett Peter Cowan at the Wolston Correctional Centre on August 5, 2016.

Judge Ian Dearden sentenced Davidson to three years' jail but with time already served he will be released on parole in late November.

The court heard Davidson plotted and watched Cowan's movements for a month to find the best way to harm the high-profile sex offender.

9NEWS exclusively revealed at the time that Davidson had screamed "this is for the people" as he poured the boiling water over Cowan.

The 31-year-old said he had seen the attack leave victims with scarring before and told police he would have loved to see that scarring on Cowan.

The convicted child-killer suffered burns to 15 percent of his body including his head, chest and legs.

The court heard Davidson claimed it was a vigilante act on behalf of Morcombe.

"I thought I can't leave here, can't live with sex predators, so I'm just going to get my own back," he said in a police interview.

The crown prosecutor said Davidson's attack was "particularly cowardly", as it was carried out while Cowan was unaware and playing cards.

Davidson told another inmate he had acted alone and Cowan "had it coming, he is a f---ing grub".

The prosecutor told the court Davidson had claimed he didn't want to kill Cowan, just for him to "feel the pain like... Daniel Morcombe would have felt".

Cowan, 48, is serving a life sentence for abducting and killing Daniel, 13, on the Sunshine Coast in December 2003.

Daniel's remains were not found until 2011, the same year Cowan was charged with his murder following an undercover police sting.

Cowan appealed his life sentence, with his legal team arguing the confession obtained through the police operation was inadmissible at trial.

However, the appeal failed.