The Independent Police Conduct Authority has found an officer used excess force during at least two arrests.
He's since left the police force.
In one case, in September 2018, the officer pushed a man back onto the bonnet of the car, took him to the ground, and knelt on his head until the officer's partner was able to handcuff him.
And in another, in March 2019, while arresting a 14-year-old boy - the officer suddenly lunged at the boy from close range, put both his hands around his neck and slammed him into the window behind.
The Authority's chair Judge Colin Doherty spoke to Māni Dunlop.
