The Crown's case was that Poi was involved in plans to smuggle contraband into the prison, whereby Leota and Samoa's partners in Auckland couriered the contraband to Napier for Poi's partner and her friend to bring to the prison on a family visiting day.
However, the contraband was instead flung out a car window upon approaching the prison on the day of March 21, 2015, after the women saw other vehicles being searched.
Manning said that it was either "anger or retaliation" that drove Leota to beat Poi in his own cell to the point where his face was "completely caved in".
The court heard Poi was in a coma for 60 days at the Hawke's Bay Hospital and is now living in a full-time care facility unable to speak or walk.
"His brain injures are so bad that you won't be hearing from him as a witness ... he's never walked again," Manning said.
It was at this point where a convicted murderer, whose name is suppressed, assisted Poi, who was laying unconscious in a pool of blood, and took him to the guard house to get help.
While Manning said this prisoner essentially saved Poi's life, he had followed "an unwritten rule that you don't co-operate with authorities" and did not disclose who had carried out the beating.
"He did what you will hear is common: that is you don't nark. He did help but he didn't tell the prison where it occurred or who was responsible."
It was several hours until Leota's involvement became known and at this point, due to the prison being in lockdown, he had been locked in his cell and cleaned up the mess, Manning said.
Luminol testing would later reveal Poi's blood in Leota's cell.
In his opening statement defence counsel Bill Calver told the jury of five men and seven women that the prisoner who helped Poi, a key witness for the Crown, was "unreliable".
In response to a question from the jury mid-afternoon Justice Clark confirmed the trial was a retrial, but said the jurors were to continue to deal with the trial as if it were any other.
