The police officer investigating the death of an inmate in his cell at Waikeria Prison says guards acted appropriately in restraining him.
Nicholas Harris died from asphyxiation while being restrained at the King Country jail in 2011 after officers believed he was trying to hang himself.
An inquest has been told the 36-year-old had threatened to kill himself and was observed on CCTV tying a sheet around his neck.
Prison officers tried to restrain him and, during the ensuing struggle, he stopped breathing and could not be revived.
Detective Senior Sergeant Ross Patterson told the Coroners Court in Hamilton on Monday he is in no doubt that prison staff acted correctly and that Harris' aggressive behaviour justified more than one officer entering the cell.
"The risk for staff has to be considered, as well as him. The motivation was self-harm. No one in Corrections ... and no one in police ever wants anybody to die in custody."
The lawyer for the Harris family, Daryl Nathan, questioned the need for such action and suggested that pepper spray may have also been used.
However, Mr Patterson says there was no evidence to support the suggestion.
Earlier, pathologist Simon Stables told the court that Harris may have died from restraint asphyxia brought on by his morbid obesity and serious heart disease. Harris weighed 192kg and had serious heart disease.
During evidence from police, a member of Harris' family started yelling that it was all lies and that he was murdered.