The family of Christchurch man Stephen Bellingham, shot dead by police in 2007, are unhappy with the formal report into what happened.
The Independent Police Conduct Authority (IPCA) report into the death of 37-year-old Mr Bellingham yesterday cleared the unnamed Christchurch senior sergeant, called Officer A, of acting unlawfully in the September 26, 2007, shooting.
It found he acted in self-defence as Mr Bellingham approached with a hammer after a violent rampage.
However, the investigation also found that the officer broke police procedures by not telling other officers he was armed or even at the scene.
The authority said the procedure breaches raised questions about the officer's approach to frontline policing and recommended he receive mentoring and training before returning to frontline duties.
Mr Bellingham's mother, Maria, said yesterday that family members were disgusted by the "Rambo-style" action taken by the officer.
"He gave Stephen 34 seconds then he lost his life. That disgusts us," she told The Press.
Mrs Bellingham denied the family was looking at launching a private prosecution, but said they were seeking legal advice over "issues" that she would not disclose.
In the meantime, they had the inquest to get through.
IPCA chairwoman Lowell Goddard found Mr Bellingham was shot after "aggressively approaching" Officer A with a raised hammer.
The force used by the senior sergeant was "not excessive in the circumstances", she said.
Mr Bellingham had been behaving irrationally, smashing a vehicle's windows and starting a fire.
Witnesses described him as acting like he was "possessed by the Devil", "talking gibberish" and "going mental" earlier in the evening.
Officer A genuinely feared for his life when he fired, and others in the area held fears for their safety, Justice Goddard said.
The senior sergeant acknowledged that he "formulated a plan in his mind", he did not advise other officers or give them any instructions on what they were to do. They arrived at the scene as he was firing.