A prisoner has admitted breaking the arm of a murderer while the pair did time inside the country's maximum security prison at Paremoremo.
Stead Nuku appeared at the High Court in Auckland today where he admitted a charge of causing grievous bodily harm when he broke Nikki Roper's arm in July.
Roper was left with a fractured skull and broken arm following the attack. He now had a titanium plate in his jaw, and suffered from hearing loss and nerve damage.
He's serving a life sentence for murdering his former girlfriend Alexsis Tovizi in 2010.
Nuku is due to be sentenced in February.
A second prisoner, Nigel Lake, is accused of taking part in the attack and is due to reappear in court in February.