The charges were laid after the death of Lee Rata who was fatally wounded by a group of people, including members of the Mongrel Mob gang, after an argument on Bonnets Rd in Kaitaia on New Year's Eve 2015.
Mongrel Mob gang member Christopher Manuel got married earlier that day and he was one of those who have admitted chasing and killing Mr Rata.
The Comers interfered with a major police investigation as both arranged for the removal of the helmet from a house and other items that were of interest to detectives. Police obtained orders from the High Court to listen to phone conversations between the father and son.
In one of the phone conversations, Gregory Matthew Comer was heard telling his father: "It's sorted, I've melted it down, stay off the phone" or words to that effect.
Manuel, 36, was sentenced to 11 years and six months for manslaughter, aggravated robbery and conspiring to pervert the course of justice, with a minimum non-parole period of five years and nine months last month.
Lester Pairama, 17, was sentenced to eight years and eight months, also for manslaughter and aggravated robbery, with no minimum non-parole period.
Both had admitted the manslaughter charges, after pleading not guilty to murder.
Joseph Martin, 41, who pleaded guilty to conspiring to pervert the course of justice and to being an accessory to murder, was jailed for three years and five months, with no minimum non-parole period, while Juanita Rafael Wilcox, 26, who admitted being an accessory to murder, was jailed for nine months with no minimum non-parole period.
On the evening of December 31, 2015, Manuel was part of a group who chased and seriously assaulted Mr Rata after an argument in Bonnetts Rd, a short distance from the wedding venue.
Mr Rata had not been invited to the wedding, but spoke with several people near the party venue, and had smashed a glass on the ground after an argument with guests, including the bride. A group, including Pairama and Manuel, chased him, yelling at him to pick up the glass.
Manuel then struck Mr Rata with a closed fist two or three times, before he was repeatedly kicked and stomped on about his head and body as he lay on the ground. One of the attackers used what police believed was a Nazi-style metal helmet to strike him about the head.
Pairama then removed the dog chain and leather vest as Mr Rata lay unconscious.
The injured man was taken to Kaitaia Hospital and was later transferred to Whangarei, where he died the next day after life support was switched off.
Manuel's wedding attire consisted of a red Mongrel Mob vest over a T-shirt, a pair of red shorts, a black bum bag. He also wore a Nazi style helmet. It's believed the helmet was used to bash Mr Rata.
