KEY POINTS:
Your teen party nightmare might not be so far-fetched. While invited guests are inside drinking or snorting anything going, hundreds of gate-crashers are milling outside. The parents are either away or in hiding. Someone says something about someone else and there's pushing and shoving and then it's all on.
Bottles fly through the window just before the cops arrive and close everything down - hopefully.
It could be worse. Someone might grab a baseball bat or a knife and use it. But fists and boots can leave a bloody - and lasting - imprint.
Police say the majority of parties don't escalate into chaos but teens say the potential is there, every Friday and Saturday night all over Auckland - or Tauranga, or Whangarei, or Christchurch, or Otaki.
Grandad might say it's the same as it ever was. But the stakes have been raised. Texting and the internet mean just about any party risks invasion by uninvited guests thrice removed (whose friends are lingering outside). That's a downside of the cellphone parents give their kids to keep them safe.
The level of violence, and the use of weapons, have escalated; the triggers for violence are lower.
Auckland After Dark
Brendan, 18 If you walk around the streets at night on weekends you are bound to come across someone who wants trouble, especially at a party. If you don't know too many people there, if someone wants trouble, you are going to be the first person they'll pick on.
Most of the parties I've been to, kids show up looking for trouble. They think they're copying the LA gangs, they show up wearing bandannas. They get it from movies and music videos showing shootings, beatings, that sort of thing.
It's something you've just got to live with. If you're with a big group you won't get a hiding.
I will go anywhere for a party. Everyone's got mates in other schools - you send a text and find out if there's any parties going on.
Crystel, 17 When certain groups arrive you just know they bring trouble but the gang issue is overblown. Every fight is not down to gangs, mostly it's just angry mates. One gets in a fight and the rest just join in.
I went to a party in Massey, everyone was drinking and towards the end these Massey people rolled up and wanted to start a fight because we were from Te Atatu. They pulled out crowbars and threw bottles.
If you know someone having the party you just turn up. Marijuana's common, ecstasy is quite big and acid. P is around but not common - you don't see people smoking it in the corner at parties. But if you want to get your hands on it you can, easily.
Angelique, 17 Teens go to parties and get smashed - I don't know why it is. You don't want to miss someone hooking up or someone making a fool of themselves when they're drunk. If you want heaps of people to come you use the internet or texting.
Youth gangs are just little wannabes who take it too far. They look at the American thing and think it's so cool.
I always leave the party at the right time and then I'll hear later by text that I just got saved by leaving at the right time. It depends who you are with and who you leave with - I always leave by myself, that's not a good thing. I walk the streets by myself when I'm wasted and feel safe as.
And, in Auckland at least, tribalism has increased. It's a city where the sons of lawyers and accountants head to parties with baseball bats in the boot, and some carry knives just in case. And where, if one kid gets picked on, he'll have a host of mates ready to fight for him. "Help" is just a text message away.
The killing last weekend of Auckland Grammar schoolboy Augustine Borrell was a bolt from the blue for Auckland's cosy, white, suburban harbour-belt. Kids from Diocesan, St Kents and Grammar partied at the Herne Bay home of lawyer Jeffrey Morrison and his wife, Noeline, who were at the Rugby World Cup in France.
Police were quick to suspect a wannabe "ABC" gang who had gatecrashed the end-of-exams party. Why? Kids from Auckland's affluent suburbs don't carry knives, do they? Stabbings happen out west or down south.
But the barriers between central, south, east and west have become increasingly blurred. Elite central schools draw aspiring youngsters from all corners; their rolls are a cultural melting pot. There's more mobility and if a party's on, kids text their mates - no one cares what school they come from.
Invariably, some will know someone who's in a wannabe gang.
Teen partygoers who spoke to the Weekend Herald say violence is now as routine to the party ritual as throwing up, groping in the dark or a visit from noise control.
"Most of the parties I've been to, kids show up looking for trouble," says Brendan. "They think they're copying the LA gangs, they show up wearing bandannas."
But fighting may break out on the basis of a look, or a Year 12 boy chatting up a Year 13's girlfriend.
"It's just testosterone," says Thomas. "Boys get angry at each other. Someone says something [about him] to one of his mates and he wants to smash them."
"It's more random than gangs consciously trying to start a fight."
With the lower drinking age, the innate teenage compulsion to test boundaries has gone to another level. Distinguishing the "good" kids from "trouble" is also harder.
"Kids booze till they drop, throw up and keep going," says an Auckland teacher. "These are kids whose parents are pillars of the community. The binge-drinking culture is alive and well."
"You're a teenager - you're meant to get drunk," said Crystel, 17. "The first time I got drunk it was 'cos everyone else was doing it. It was just what you're meant to do."
The seeds of a feud may be sown in the playground. "It used to happen all the time at school," says Ethan. "People would try to start stuff. Then you see them under the influence at a party and beat the crap out of them."
Even Auckland Grammar has a white supremacist gang of sixth formers who go around bashing small-fry.
"I've been at parties where people just want to fight for the sake of starting a fight," says Angelique, a Year 13 student at a West Auckland school. "It usually starts over something stupid like a boy chatting up a beautiful girl and her boyfriend starts a fight."
It's no different in the city's posh inner-east. "Fights at parties can start from gossip," says Michele, 18. "People hear something about someone and beat them up without knowing who they are or if the gossip about them is true."
Michele recalls a Greenlane party where members of the ROC gang were refused admission and laid siege to the house, throwing bottles and smashing windows. "This big guy from the first XV went out to get them to go away and they started throwing things at him. Down the road they found people walking to the party and beat them up."
Crystel: "When certain groups arrive you just know they bring trouble."
Staunchness, a refusal to back down, can prove fatal when the provocateur is out of it and has a knife in his pocket.
The police initially linked the Herne Bay stabbing to gatecrashers from an "ABC" gang. They've seen the pattern. "They start out doing minor stuff, as their confidence grows they progress to more violent robberies and straight beatings," says former youth court prosecutor John Williams. "You get 13 and 14-year-olds joining up with older kids. The level of violence they are using - they don't think twice about kicking someone in the head. These people have no fear."
But most ABC gangs aren't gangs in the traditional, structured sense - they are loose groups of friends who give themselves a name, adopt colours and bandannas. Some just watch out for each other, others talk big but do very little. A few carry knives and offensive weapons and do aggravated robberies.
Augustine Borrell, everyone says, was a good kid - a top boxer and rugby player who wouldn't hurt anyone. But even he was part of a "crew" - a wider circle of friends who look out for each other. Their worst crime might have been tagging, and watching gangster videos.
"There's two types of crews," says one student, "those that aren't looking for trouble - but if trouble comes they are there - then there's guys that are looking for trouble. When a troublemaking crew runs into a non-troublemaking crew, that's when it starts."
If someone gets picked on at a party, or outside, they can always text for reinforcements.
Lynette Norton's son was the victim of a random assault at a Glendowie party three years ago. Two gatecrashers asked to leave had an altercation with a stranger on the street. Shortly after, a car arrived at the house.
"A group of bandanna-wearing males with a variety of weapons appeared, knocked my son unconscious from behind then kicked his head in, smashed in the windows of the car in the carport plus the front door, whacked three others unconscious, stormed through the house, terrifying all, then left.
"Although my son was unrecognisable he survived and recovered after some weeks."
She still finds it unacceptable that the police were not interested in investigating. "These kids had baseball bats and homemade knives and used the legs off tables - once they get away with it, what might they go on to?"
Norton says otherwise law-abiding kids now carry baseball bats and knives for protection.
"As parents, we don't really know what our kids are doing. You get kids from very deprived backgrounds with issues and very affluent kids with other issues."
The trend to carry weapons creates a dilemma for police: do they believe the kid when he claims it's for self-defence or risk him using it on someone?
Police say it is misleading to portray the teen party circuit as a minefield. But what they then go on to tell you is hardly reassuring. It's a matter of degrees.
Constable Nigel Turnbull heads an Avondale-based police youth action team at the frontline of youth offending. It's irresponsible to equate parties with trouble, he says. "There're different levels - there're teen parties that breach liquor provisions or bylaws, but by and large they are just a party that's alcohol-fuelled.
"There are normal parties where scraps occur and some with different levels of drama. There have been assaults with weapons where gangs have turned up, there have been rapes. The level of violence some of these street gangs are using is a lot more significant than maybe the one-on-one scraps when I was at school 15 years ago.
"My personal feeling is with the lower drinking age there is a lot more alcohol readily accessible to young people. It hacks me off that Parliament didn't raise the drinking age when they reviewed it recently.
"My eldest girl's at intermediate - within a few years she'll be wanting to hang out with mates and stay over. What level of concern do you have to have?"
Late last year, it seemed LA gangster culture really had taken root in Auckland after nine street killings, mostly in South Auckland, in eight months. The killers were young men in their late-teens or early 20s, gathering in parks, getting high then cruising the streets with knives or baseball bats, looking for trouble. In pockets of the western suburbs, run-of-the-mill dairy and service station robberies became aggravated robberies and street robberies with over-the-top violence. The North Shore has its pockets too, where rival gangs sort out tensions with baseball bats.
There's more fuelling this hatred than alcohol, says John Williams. Some kids come from deprived backgrounds, many identify with American hardcore rap lyrics and videos.
"There's a whole mix of [causes]: stuff they are exposed to on TV, or video games where people get knocked down and just get back up. We've got two to three generations of kids brought up badly. They get involved with kids that use violence for the fun of it."
But it's significant that Herne Bay was the first street killing in Auckland since November. Police and community initiatives - including targeting known offenders and enforcing bail conditions and curfews - clearly have made a difference. Many of the ringleaders are now locked up; others are turning their lives around.
We can't say much about the 18-year-old charged with Augustine's murder but the ingredients appear familiar. His address was given as Otahuhu but it's known he spent most of his teenage years in the inner-west, where he went to school.
On Monday, as the Herne Bay killing was front-page news, the Herald also reported the conviction of Jio-Pene Sauaki, found guilty of the fatal stabbing in Manurewa in July last year of 18-year-old Kelly Lawrence.
The circumstances were similar to the Herne Bay killing and last October's fatal stabbing of 14-year-old Manaola Kaumeafaiva outside a Hip-hop for God function at Avondale College: good kids in the wrong place at the wrong time falling victim to an out-of-it kid looking for trouble.
Jio-Pene's mother, Linda Sauaki, in an interview with police reporter Elizabeth Binning, urged parents to take more responsibility. "If [kids] want to get dropped off somewhere at night, make sure it's safe. If you know you can't be at a place [to pick them up], then find another parent who can."
In the western suburbs of Auckland City, it's not unusual for fathers to turn up and act as bouncers at the gate, says the police's Nigel Turnbull. "They have lists of people who are not allowed in. When someone turns up who's on the list the first thing they do is call the police. We have families who ring to advise us 'we're holding a party and 50 people are invited - we just want to let you know and we'll call you if there's a problem.
"We've been asked to close down a few parties in recent weeks because a couple of hundred people turned up.
"A lot more parents are a lot more concerned about it."
