Craig Rippon died on November 8 last year.
A Whanganui man has been sentenced to a minimum of 12 years in prison for the murder of Craig "Rip" Rippon.
Mr Rippon, a Black Power leader and member of the gang since the 70s, died in hospital after being assaulted at a house in Rimu St, Gonville, on November 8. He was a founder of the award-winning Matipo Development Trust which helped vulnerable families in Whanganui.
Tyrone William Madams, 39, pleaded guilty to murder in March. He is one of six defendants in the case.
Matthew Thomas Madams, 37, Kevin Roy Madams, 42, Tyrone Peter Madams, 57, and two youth have pleaded not guilty to the murder, as well as a charge of participating in a criminal organisation. They will go to trial in October.
Justice Karen Clark said Tyrone Williams Madams swung a spade down on Mr Rippon's head "as he lay defenceless on the ground".
Mr Rippon was left unconscious where he was, and later died in hospital from "extensive head injuries".
Crown prosecutor Harry Mallalieu said Mr Rippon's family's loss was "immeasurable".
Defence lawyer Debbie Goodlet said Madams committed the murder out of "reckless disregard" as opposed to attacking Mr Rippon with an intent to kill him.
"His instructions have always been clear: 'I feel guilty, I am guilty.'"
Before sentencing, Justice Clark told Madams he could have a seat, but he declined.
"I don't deserve to sit, miss," he said.
Many details of the offending have been suppressed to ensure a fair trial for the other five defendants.
Justice Clark said Madams knew the victim well. "You and Mr Rippon - Uncle Rip - were close."
She considered if Madams could attack Mr Rippon in such a way, despite being close to him, "it is reasonable to assume that those who are strangers to you may be at even greater risk.
"Protection of the community features strongly in my mind."
She noted Madams was "extremely remorseful", although pointed to a concern in a report quoting Madams as saying if it has been someone else "It wouldn't be that bad".
However, Justice Clark accepted the explanation Madams meant his own grief wouldn't be so bad. She believed Madams would still have remorse if it had been someone else.
Justice Clark finished the sentencing with an "observation".
She noted Madams himself had had an experience being hit on the head with a weapon, with the difference being that he woke up afterwards.
"How normalised these acts of brutality have become for you and others who have been similarly exposed and similarly offend."
The prison sentence would be beneficial for him, she said.
"You will have the opportunity to embark on what you have been trying to achieve but have found impossible."
Justice Clark said Madams would be able to distance himself from his "dysfunctional life", have a chance to work towards an education, and benefit from monitoring of his safety and mental health.
She sentenced him to life imprisonment with a 12 year non parole period.