The Independent Police Conduct Authority has found officers were justified in shooting Vaughan Te Moananui at his sister's house in Thames in May last year.
Mr Te Moananui had been under the care of the Waikato District Health Board mental health team, and the police database described him as severely mentally unwell and extremely violent.
The authority said he had shot a man in the foot the night before and told his sister he wanted to "go out like a gangster, giving Thames something to talk about".
On the day he was shot, Mr Te Moananui had covered his body in mud, pointed his gun at cars and said he wanted to be shot by officers, the report said.
His mother had contacted the DHB because he was acting in a paranoid and threatening manner.
The armed offenders squad accompanied a mental health worker to Mr Te Moananui's sister's house.
The authority said he pointed his gun at two officers and was shot after ignoring police challenges to drop his gun.