As a child, Quinn Patterson was forced to help his "eccentric" father dig graves and was the one who stepped in when his parents were fighting.

Before long he was in trouble with the law - with several convictions by age 22, including one for stabbing a policeman.

Fast forward 34 years and the troubled father of two is dead - his charred remains last night recovered from his rented home which burnt to the ground after he shot three people during a routine property inspection.

One of five siblings, Patterson moved to New Zealand from Canada with his parents and they settled in Katikati.

Patterson told friends his gravedigging father was intelligent but "a bit of an eccentric", very spiritual, and had a strange beliefs about the world.

Friend Leah Cameron said Quinn's father brought his children up with a "Doomsday" mentality.

"He was fatalistic about the world, that it was not a good place ... He could have been classed as being a bit of a fanatic".

He made his children dig graves with him and he and his wife apparently wrote a book about UFOs.

One friend said Patterson's father was strict but loved his children very much.

"His dad was tough but he was brought up in the depression. He was just a hard man but he had the love of God in him. He loved his sons (and daughter) very much."

But Cameron said: "These kids were hammered.

"His father used to get a bit aggro with his mother. Quinn was the protector of the mother. He always tried to help. He was the least aggressive in the family. But growing up in his very troubled family, he got into trouble quite a lot."

That trouble included several brushes with the law and by age 21, he had an assault conviction.

Another friend, who didn't want to be identified, said one of Patterson's first big brushes with the law took place at the Whitianga Pub. He had told friends he'd been beaten up by some guys during a fight and he wanted retribution.

He went to the pub with the group of friends and there was a "big fight, there were guys with massive injuries all over the place". Several ambulances were needed to treat the injured.

The next day armed police turned up at the place Patterson was staying and he and his friends were arrested.

Soon after, police dog handler Bruce Howat caught him writing graffiti on the wall in a central Hamilton street - within 100 yards of the police station.

Patterson ran off. Howat gave chase and Patterson stabbed his arm several times with a 13-inch hunting knife, scarring him for life and ending his career.

"He was a little runt who wore glasses," Howat told the Herald.

"He was so small that after he stabbed me, I picked him up by the belt with one hand and tried to carry him back to the police station."

After "four or five" mistrials - Howat said Patterson appealed the case - he was finally convicted in 1984 and sentenced to 18 months for grievous bodily harm.

When he got out of jail the following year, Howat says he was told Patterson had gone overseas while on parole.

Over the next 20 years he had two children of his own and by 2007 he was running his own business in Whangarei - with locals unaware of his violent past.

He rented several different properties in the town, and had clashes with previous landlords over unpaid rent and expenses.

By about 2010, he was single and living alone on Mt Tiger Road in rural Whangarei in one of two homes on the property, the other being empty.

Patterson ran Ab Fab House Maintainance Services from the house. The three reviews on a website for New Zealand businesses were positive but are from several years ago and it is believed he was struggling financially due to work drying up.

Like his father, he was known around town as "a little unusual", intelligent but temperamental.

"He was a man who would always speak his mind," said Cameron.

"We'd often get into conflict because he was so honest. And he didn't socialise well with people because he could see right through people and found most were either selfish or not genuine."

And he was very protective of his property, not letting anyone inside.

"I turned in there one day, and he would always come out and make sure he wouldn't let you into his house - that's for sure," said neighbour Brad Walters.

Patterson attended local community meetings to help with pest control.

"He was getting letters out to neighbours to make sure people knew who was who, and have a get-together, so he did come across as pretty good as long as you didn't enter into his property," said Walters.

Patterson liked guns despite friends saying he did not have a licence and was not a hunter. Neighbours would often hear him shooting in his backyard.

"He just shot in his back lawn by the sounds of it, you could hear it from here, you could hear it from everywhere," Walters said.

"They were big guns ... we're talking automatics, semi-automatics, big calibres. They sounded like cannons, you could hear them going off with, like, 16 rounds.

"He was just sort of a law unto his own."

He became paranoid and started to accumulate several weapons. A friend told Newshub he had grenades, shotguns, rifles and hand guns. He had "barricaded" himself in the property with bars on the windows.

He was becoming more and more depressed and paranoid, friends said.

He had taken several types of medication over the years, including sleeping tablets and had tried natural medication, vitamins and exercise in an attempt to get better.

He told friends and family that new tenants had moved into the other home on the property, which he regarded as his "sanctuary".

He felt as thought he was being pushed out of the home and his property manager Wendy Campbell had keys to the property and had visited, which angered him.

"The thought of moving was incredibly stressful for him," Cameron said.

"I feel that was the catalyst for snapping."

Patterson texted Cameron two weeks ago with suicidal thoughts.

"Looking over my life, I see everything I love torn from me," he said.

"I don't want to be here. Nobody else wants me here and you were right about me, I'm continually struggling.

"This life is just a continual struggle without end or point and I'm done with it. Each day I wake and realise to my dismay that I'm still here. Yesterday it was so dark, like there was no sun. Each day is worse.

"Depression is an understatement. No light at the end of the tunnel, just constant unending dark."

Cameron texted back, saying 'Let's work this out and find a solution'. But Patterson responded that the world was "no place for me".

Wendy Campbell's friend Julie Pepper said Patterson was "intimidating and aggressive" toward her.

On Wednesday morning, Campbell, 60, arrived at the house with her daughter Natanya, 37, who recently started working her company, Seek n Find, which she ran with husband Tony Rodgers.

They were there to carry out an inspection and install smoke alarms with contractor Jeff Pipe.

But Patterson "lost the plot" and shot the two women dead. He shot and maimed Pipe, who was able to escape in his Suzuki.

Patterson phoned his sister in Auckland afterwards and left a message.

His own life ended after a gunfight with police, with the house burning to the ground.

The sister said she believed he killed himself because of the tragic nature of his actions.

"He would have thought what he did was terrible and that's why he killed himself. He was never of that nature. Physically hurting people deliberately - no, it was never his thing."

Patterson's texts to Leah Cameron

"Looking over my life, I see everything I love torn from me. I don't want to be here. Nobody else wants me here and you were right about me, I'm continually struggling.

"This life is just a continual struggle without end or point and I'm done with it. Each day I wake and realise to my dismay that I'm still here. Yesterday it was so dark, like there was no sun. Each day is worse.

"Depression is an understatement. No light at the end of the tunnel, just constant unending dark."

Cameron: 'Let's work this out and find a solution'.

Patterson: "What can you do? This world is no place for me."

WHERE TO GET HELP:

If you are worried about your or someone else's mental health, the best place to get help is your GP or local mental health provider. However, if you or someone else is in danger or endangering others, call police immediately on 111.

OR IF YOU NEED TO TALK TO SOMEONE ELSE:

• LIFELINE: 0800 543 354 (available 24/7)
• SUICIDE CRISIS HELPLINE: 0508 828 865 (0508 TAUTOKO) (available 24/7)
• YOUTHLINE: 0800 376 633
• NEED TO TALK? Free call or text 1737 (available 24/7)
• KIDSLINE: 0800 543 754 (available 24/7)
• WHATSUP: 0800 942 8787 (1pm to 11pm)
• DEPRESSION HELPLINE: 0800 111 757