The force used by an Auckland police officer against a teenager during an arrest was unjustified and excessive, the Independent Police Conduct Authority has found.
A 14-year-old male suffered a cut to his forehead and a broken wrist during his arrest on March 29 last year.
"The Authority believes the degree of force used upon Mr X (14-year-old) was not necessary and was unreasonable."
Between 11.30pm on March 28 and 3.30am on March 29, the teen and five others between the age of 12 and 14 stole a Mazda vehicle from a Massey address and proceeded to go on a "joy ride."
They sparked police's attention around 3.30am as they were speeding and had ran a red light. When signalled to pull over, they refused to stop for police and sped off.
The car was then tracked by helicopter, traffic cameras and long-range observation as it made its way around various Auckland motorways.
It was eventually stopped nearly an hour later around 4.25am after being spiked near Silverdale.
The teens refused to get out of the car and locked the doors which led to a police officer smashing the driver's side window.
"Officers again instructed the youths to get out of the car. When they failed to do so, officers removed four of them and the last two got out on their own."
The injured teen was grabbed by the police officer and "thrown" to the ground and landed face down.
The officer indicated he struggled to handcuff the boy who was wearing rubber gloves in an effort to avoid leaving fingerprints in the vehicle.
When pulled up, the officer had noticed immediately that the boy's head was bleeding but wasn't made aware of his broken wrist until half an hour later.
There had also been claims that the officer kicked and stomped on the boy's head but the Authority believed these claims were not true.
"Officer A denies kicking or stomping on Mr X. Two of the youths said they saw the arrest but there was no kick or stomp.
"Therefore, we believe there was no kick or stomp on Mr X, and he suffered the cut to his
forehead when his head struck the motorway surface. It is possible Mr X was dazed after his head hit the ground, as he said."
The Authority also believed that the teen's wrist was most likely broken from the impact of hitting the ground.
"But it is also possible this occurred, or was made worse, when the officer applied
handcuffs in the way he describes."
All of the occupants of the vehicle were arrested and taken into custody but none other than the 14-year-old were injured.