Key Points:

Pihema Cameron was angry and upset, his mum Leanne says, angry at her.

On January 26, he went swimming with his friends and cousins at the beach, where he told them that his mother hadn't yet managed to save enough money to fly him to Perth where she was seeking work.

"That's why he started drinking," Leanne Cameron says. "I mean, he was only 15 - a kid."

Normally, Pihema's curfew was 8pm - but without his mother to supervise, that had fallen by the wayside. He had drunk the equivalent of four or five beers, some vodka mixers and had smoked a cannabis joint.

Back in Manurewa, he and a 16-year-old friend stayed out, "just fooling
around" with spray cans. He had never been in trouble with police, and his mother didn't know he was a tagger. The one time he had tagged a table at home with a permanent marker, she had made him scrub it off.

Walking home, Pihema tagged an electrical relay box and then the roller door on the front of a corner house.

Bruce Emery was sitting on his patio, sipping an iced tea, when he saw two figures in hoods and heard the shaking of a spray can. His fence and mailbox had been tagged before - but never his garage door. Leaping to his feet, he angrily shouted: "Oi, what the hell are you doing?"

"When I yelled out, he just kept on spraying," Emery said.

In bare feet he raced downstairs, grabbed the first weapon that came to
hand - a fishing knife - and chased the boys down the street. He caught them 365m down the road, and Pihema died of a 5cm stab wound to the chest.

Pihema's friend cradled the younger boy as he died.

Emery, meanwhile, said he did not know he had killed the boy. He went
home, cleaned the knife, and hid it under his mattress. Somebody else
called the police.

"I was terrified," Emery said. "I mean, only a week before, the young Indian guy got stabbed at the dairy by a 15-year-old; another Indian dairy owner down the road from us, he got whacked in the head. There
are a lot of things down there that don't make the papers."

The angry Emery identified with the stabbing victim - not the knife-
wielding assailant.

Law and order groups such as the Sensible Sentencing Trust are usually the first to call for tough sentences for violent criminals, but this time they sided with the middle-aged self-employed upholsterer. Somehow,
when the killer is a middle-class businessman, the tables are turned.

When Northland farmer Paul McIntyre shot and injured a thief trying to
steal his quad bike in 2002, a jury acquitted him. When gun store owner Greg Carvell opened fire on a machete-wielding robber in 2006, police dropped charges.

Now, South Auckland liquor store owner Virender Singh is facing charges for injuring two alleged armed robbers earlier this year. Politicians queued to be photographed by Singh's hospital bed during the election campaign, as they sought to redraw the line of self-defence.

Emery's jury concluded that the line was 365m down Mahia Rd, convicting him of manslaughter but not of murder. They accepted that he had not acted with intent.

Leanne Cameron, who like most mothers believed her son could do no wrong, did not even find out how Pihema had died until she had taken out a loan to catch a flight to Auckland.

She picked up the New Zealand Herald, and discovered he had been stabbed by a 50-year-old man.

"It didn't make sense to me," she says. "The fact this old man chased after the boys. The fact my son's friend had to hold my dying son in his arms."

Leanne reserved most of the blame for Emery - "I have never felt this hatred; he took away my only son" - but saved some, like most mothers, for herself.

"I do feel guilt I wasn't there to protect Pihema," she says. "I would have cleaned that paint off his house wherever it was. I would have made Pihema apologise personally.

"We, as parents, have to learn from this. If you see spray cans in your kid's room, hit them up about it. If your kids are going out at night, ask them questions ... don't assume nothing in life. Life is too short."