A police officer in Tonga on duty the night of an alleged assault on Kali Fungavaka says he saw the New Zealand policeman being held in a choke hold.
He was among four officers giving evidence in a preliminary inquiry following the death of Mr Fungavaka in August last year after being taken into police custody.
Mr Fungavaka had been arrested on a minor drunkenness charge while in Tonga for a family funeral.
Six people including five policemen have been charged with manslaughter and an alternative charge of causing grievous bodily harm.
Our correspondent, Vovui Fotu of Radio Tonga, says there are 32 witnesses giving evidence at the inquiry at the Nuku'alofa Magistrate's Court.
"The court heard today that one of the police officers who worked on that night saw one of the accused choke-hold Constable Fungavaka to control him and only let him go when he turned blue-black. He also said another accused stamped on the victim's head causing him to pass out."
Vovui Fotu says the names of the accused have been suppressed.