A Whangarei constable's future in the police force will now be scrutinised after he was convicted of assaulting a handcuffed teenager in the back of a patrol car.

Judge Stan Thorburn delivered his decision in Whangarei District Court yesterday but did not hand out any other penalty to Constable Richard Soper.

Lawyer Arthur Fairley sought a discharge without conviction for the constable after he was found guilty in a judge-alone trial of assaulting Wiremu Henare, now aged 18, while Henare was handcuffed in the back of a police car in August last year.

Henare and an associate earlier went to an elderly woman's home in Maunu and Henare hit the 68-year-old woman several times with her walking stick before stealing her Audi.


When police tried to stop him, he fled, reaching speeds of up to 160km/h before crashing at One Tree Point.

However, in convicting the officer the judge raised concerns over infrastructure available for hard-working officers to deal with a "day to day diet" of crime and any stresses in their personal lives.

Judge Thorburn was concerned such a "diet" would consume the soul of a police officer.

He said Soper had taken his personal stress over his wife's health to work and it took a toll on his discipline.

Northland police boss Superintendent Russell le Prou would not comment on Soper's case specifically but was satisfied there were a number of avenues staff could access if they were under stress for any reason.

"Each district has a welfare officer that staff can speak to at anytime. They can also use the services of the Employee Assistance Programme (EAP) or they can speak with their supervisor," said Mr le Prou. "All these processes work very well for staff and are easily accessed."

Once an officer was convicted, a disciplinary process could commence and an initial meeting would be held to discuss the matter and the process to follow.

That usually involved senior district staff.

During the trial, Henare said Soper punched him up to 10 times in the back of the police car. Soper denied punching Henare at all but did admit he pushed Henare's face in the back of the car as the prisoner had pushed his face into the officer's face. Soper also said he was disgusted at Henare's earlier behaviour in hitting the elderly lady with her walking stick during the home invasion.

"There is an expectation of trust that a police officer's conduct, when dealing with a suspect, will be with integrity and follow processes. This incident broke all these expectations," Judge Thorburn said.

"The importance of a police officer diligently committing to proper procedures and ensuring in all circumstances there is no succumbing to personal overflow or outrage, anger and/or ill-discipline can't be overstated. The arrest process does not enable a police officer to mete out his or her own summary punishment."

New Zealand police prosecutor Gul Qaisrani said the public expected a certain standard of conduct by police officers.

"A clear message needs to be given to the community that police do not accept this kind of attitude from their current serving police officers. The perception he (Henare) might have got what he deserved is irrelevant.

"He was vulnerable and he was handcuffed."