Three men appeared in a Tongan court on Friday following the death of a New Zealand police officer.
Kali Fungavaka died in a Nuku'alofa hospital on Thursday night.
He was assaulted in a Tongan police cell after being arrested on a minor drunkenness charge.
Tongan police say the man they believe assaulted Mr Fungavaka has appeared in court charged with causing grievous bodily harm.
However, acting Police Commissioner Siopesoaki Motu'apuaka says he may face more serious charges.
Two police officers have also appeared in court charged with common assault.
All three are remanded in custody and will appear in court again on Monday.
It's expected Mr Fungavaka's body will be flown back to New Zealand on Saturday. He had been in Tonga for the funeral of his grandfather.
Mr Motu'apuaka says the police investigation is ongoing, with the assistance of New Zealand police.
He says the Tongan prime minister and senior police officers have visited Mr Fungavaka's widow to pay their respects.
New Zealand police say Mr Fungavaka, who had been an officer since 2007, was humble and passionate about making a difference, especially in the Polynesian community.
They say he got a bravery award in 2006 for going to the aid of a woman who was engulfed in a ball of flames.
'A role model to his fellow officers'
At a media conference on Friday, Counties Manukau police commander John Timms said Mr Fungavaka was a role model to his fellow officers and the Pacific community.
He said police wanted to celebrate his life and acknowledge the contribution he made to the force.
A fellow constable and friend of Mr Fungavaka said the death had been an emotional roller-coaster for the police community.
Earlier on Friday, a former police commissioner for Tonga, Chris Kelley, said he was shocked to learn of the death.
Mr Kelley told Morning Report that violence - often involving alcohol abuse - was prevalent while he was commissioner but he hopes changes made during his tenure, which ended last year, have reduced it.