This is Venezuela, where more than 14,000 people were murdered last year, according to human rights groups. That is about three times bloodier than Iraq,

It started one humid afternoon when a seven-year-old boy flicked something out of a schoolbus window at a teenager on García de Sena street. Some say it was a piece of popcorn, others a rolled up piece of paper. Whatever it was, the older boy took umbrage. He strode to the window and slapped the child, sending him home crying to El Cementerio, a few blocks up the hill.

The mother, aunts and sisters stomped down the hill and confronted the teenager, jabbed him, prompting his own female relatives to jab back. Insults flew. That night, shots were fired into El Cementerio. The neighbourhood did not see who was shooting but returned fire. And so began another war.

Eight months and multiple ambushes later seven youths from El Cementerio are dead, as are an uncertain number of their rivals down the hill. Richard Nuñez, the soft-spoken leader of the Cementerio youths, lifts his T-shirt to show fresh scars on his belly, back and right arm. "They got me when I was riding past the police station, shot me right up." He survived, but wonders if he will be as lucky the next time. "Things are pretty hot. This isn't over."

Over. A hopeful word. As if the violence has a destination, an end point. This is Venezuela, where more than 14,000 people were murdered last year, according to human rights groups. That is about three times bloodier than Iraq, which has a similar population. The government does not publish full statistics but says the official murder rate is 48 per 100,000 people, more than double South America's average. Some estimate the rate in Caracas to be as high as 140 per 100,000, making it one of the world's deadliest capitals. Hospital emergency wards overflow, especially at weekends, with bleeding, punctured casualties. Corpses stack up in morgues while grief-stricken relatives gather outside, noses cupped against the smell.

What makes this corner of South America, once best known for oil and beauty queens, a Hobbesian lottery? The short answer is gangs. Young men with guns drop bodies as they battle over turf and drugs in winding, rubbish-strewn streets. The catch-all description for them is malandros, supposedly feral thugs and ne'er-do-wells perpetually at war with themselves and the rest of society. They inhabit, Venezuelans tell you, the land "up there": hillside barrios. Malandros flit across television screens and newspapers as cadavers or hooded suspects paraded by police. Either way they are anonymous cyphers who do not speak, leaving their motivations, their world, incomprehensible to outsiders. A war over a piece of popcorn?

This is the story of one gang. Of its rise and fall and resurrection in a dusty, sun-baked slum, and of the reasons it does what it does. Some of the plots and characters make US crime dramas seem tame. There is the hitman who became a minister's bodyguard. The straight-A student suspected of black magic because no one can kill him. The mugger who found love while dodging police. The prison cannibal who found God. And the aristocratic rum merchant who proved an unlikely saviour. The narrative tilts between decay and hope, corruption and redemption.

Fifty years ago El Consejo was a sleepy farming village of 2,000 people ringed by sugar cane plantations. Today it is home to 50,000 people, none of whom farm, and whose brick-and-tin homes cling to steep slopes. It is a community marooned without jobs and proper housing by dysfunctional oil booms that stunted industry and agriculture.

Caracas is 60km east, at the end of a potholed motorway, but El Consejo feels like a ramshackle extension of it. Tucked into its concrete mazes, unmarked on most maps, is the two-block neighbourhood of El Cementerio, so named because it abuts a graveyard. Here, says Jimin Perez, a former police officer, is where you don't want to stop and ask directions. "The kids stick a gun in your face and steal your things. Then the adults dismantle your car for parts. If you make it out and go back with the police, no one has seen anything."

This is the fiefdom of the cemetery gang: two narrow roads lined with bleached houses from which eyes appraise all who enter and leave. Everybody knows each other, and many are related. Most men are gone – absconded, dead, jailed – leaving wives and widows as matriarchs to raise broods alone. The nearest school, Manuel Cipriano Perez, is so overcrowded its 1,117 students are rotated in two shifts. Often there is no electricity or air conditioning, so pupils slump in the tropical heat. The computer room is locked and empty. "Children don't have many recreation options," says Damaris Costa, the director. "They throw stones at their own school."

A five-minute walk down the hill from El Cementerio brings you to identical-looking streets, but this is the territory of Los Pelucos (The Wigs), the other gang in the "popcorn war". Walk 10 minutes west and you are in the territory of the 5 de Julio (Fifth of July) gang. It too is at war with El Cementerio but over a motorbike stolen in 2008. Bubbling under these disputes is competition to sell drugs, mostly cannabis and cocaine, to outsiders.