Janio Heinrich used to promote peace on the streets of Grande Bom Jardim before he was shot dead two months ago. Now his face stares out from a large mural on a dusty street, a tribute to the 18-year-old whose crime was to enter the turf of a gang that does not dominate his area.

Residents are used to seeing memorials to their young people in this low-income part of Fortaleza; reaching adulthood here means surviving one of the deadliest districts of Brazil’s most murderous city for young people.

With 414 murders of adolescents aged 10-19, in 2017 Fortaleza became the youth murder capital of a country that broke its own record for homicides nationwide last year. In recent years the violence has grown increasingly brutal, with attackers parading torture, decapitations and executions in grisly social media posts.

But in that time the north-eastern city of 2.6 million people has also become the epicentre of a growing movement to demand action to protect poor, mainly black teenagers and keep them alive.

Renato Roseno, who heads the campaign Cada Vida Importa (Every Life Matters), is in no doubt that it is possible to end the violence in the state of Ceará, of which Fortaleza is the capital. For two years the Socialism and Liberty party (PSOL) congressman has been mobilising support from the state government, international agencies and community organisations – and amassing a huge body of evidence – to back him in his mission.

“To live in a city where every day a kid under 19 is killed is so shameful and painful. But we are 100% certain these deaths are preventable. We know who the victims are, we know they are young black people living in very poor areas, for example. We know they are the sons and daughters of very young mothers,” says Roseno. “We have all the information we need.”

Facebook Twitter Pinterest Renato Roseno speaks at the launch of the first week to prevent youth homicides in the state of Ceará. Photograph: Phil Clarke Hill/The Guardian

He points to cities, such as Bogotá and Cali in Colombia, where policies including changes to the public security model and investment in social urbanisation have helped bring down the murder rate at the same time as it was rising in Fortaleza, amid the spread of the drugs trade and escalating conflict between four trafficking gangs, an influx of weapons and police and institutional brutality.

However, Roseno believes his reforms could face additional hurdles in the form of Brazil’s incoming government.

“Brazil is now at a critical point,” he says, referring to president-elect Jair Bolsonaro’s backing for looser gun laws, mass incarceration, immunity for police who kill in the line of duty and a lower age of criminal responsibility. “We risk entering an era like the Philippines is going through under [President] Duterte.”

In November, Roseno was at the city’s São Luiz theatre for the launch of Ceará’s first official week to prevent youth murders. The week coincides with the anniversary of the 2015 Curió-Messejana massacre, when military police in Fortaleza shot dead 11 people, including nine young people aged 16-19, in an apparent revenge attack for the murder of an officer.

Among the victims was Edna Carla Souza’s 17-year-old son Alef. Today she travels around Brazil with six other “mothers of Curió” to demand justice. Forty-four police were arrested and questioned over those deaths, and 33 are now awaiting a possible trial.

Facebook Twitter Pinterest Edna Carla Souza, whose son Alef was shot dead by military police in November 2015. Photograph: Phil Clarke Hill/The Guardian

“Alef told me he wanted to be a soldier in the Brazilian army but he never reached 18. That’s what hurts most,” she says. “There are young people living on the [city’s margins] who have dreams and ambitions like anyone else.”

Roseno highlights the rampant inequality in Fortaleza, whose beaches and high-rise hotels in the city centre draw tourists from all over Brazil. “Mothers say to me, ‘It’s like the lives of our sons are worthless.’ The kids who are being killed are the poor. We have to take responsibility. This is a social, political and economic problem but it’s also an ethical problem.”

An end to police impunity as part of better policing is among 12 measures proposed by Roseno’s committee. Its agenda is about more than social welfare policies, Roseno insists. Instead, it calls for specific actions to prevent murders of vulnerable young people. The proposals are based on research with 224 families of murdered young people, analysing the victims’ lives and deaths, for example, examining the infrastructure in 17 of Fortaleza’s 119 districts where almost half of all murders occurred.

The report, which won a UN prize, includes measures ranging from restricting Fortaleza’s excessive, lurid TV coverage of murders to more education about drugs. A finding that 60% of victims had dropped out of school, for example, has led the committee to pressure successfully for better monitoring of attendance.

Facebook Twitter Pinterest A street in Grande Bom Jardim, a low-income district of Fortaleza with one of the highest rates of youth homicides. Photograph: Phil Clarke Hill/The Guardian

It also calls for improvements to the state’s juvenile detention centres, the focus of strong criticism from the Inter-American Commission of Human Rights for overcrowding, squalor and lack of educational opportunities that trigger deadly riots. “The lack of basic education in these facilities must be addressed. If a youth is detained for three years, he will never recover those lost years of education,” says Mara Carneiro, of human rights organisation Cedeca.

She highlights the segregation of youths in blocks according to the gangs that rule their home district and lack of “neutral” blocks that are not tied to a gang.

*Eduardo, now 18, recalls a riot earlier this year at the centre where he was serving time for armed robbery. An inmate killed his cellmate with a weapon made from metal bars. “I survived by holding up a cushion but he stabbed me 15 times, injuring my lungs,” he says, adding that youths who are not in gangs when they enter the centres join them for protection.

Talking to Eduardo, experts and residents in Grande Bom Jardim, it is impossible to overstate the violence that is a backdrop to daily life for many. Everyone has a story of losing a young relative, neighbour or friend, of death threats on social media, of fear of the military police or gangs, of the killings going unpunished.

But even the frontline workers are shocked by the escalation in murders of girls, which rose more than 400% in Fortaleza in 2018, for the second consecutive year, and by the brutality of attacks, including decapitations and dismemberments.

Facebook Twitter Pinterest Street poets and rappers who campaign against youth violence in Fortaleza. Photograph: Phil Clarke Hill/The Guardian

“We don’t yet understand this new level of brutality,” says Rogério Costa, one of the few who still crosses safely between gang territories in Grande Bom Jardim. He and colleagues at the Herbert de Souza Centre for the Defence of Life engage local youths in programmes and cultural activities to protect and educate them.

“There is a lack of public policy to respond to this young population,” Costa says. “We have the absence of the state and, where the state is present, a lack of respect for human rights and violent practices. This creates a barrier. We have a bad justice system so that people decide to settle their disputes on their own.”

Those trying to prevent the murders also face risks. Last year, death threats forced Roseno to take police protection and today he goes nowhere alone. But he won’t give up. “This is the most urgent problem facing our society. We have to persuade people that our agenda of democracy, human rights, and social justice is the better agenda for Brazil … as long as people don’t have access to wealth, knowledge and power there will not be peace.”

And teenagers like Janio Heinrich will continue to be memorialised on the walls of Grande Bom Jardim.