Rio de Janeiro (AFP) - While the fighting in Rio de Janeiro's crime war is done by commando-style police and heavily armed drug traffickers, a growing number of the victims look quite different: innocent, joyful children like Maria Eduarda.

Firefights erupt in densely packed, poor favela neighborhoods, leaving thousands of people with nowhere to hide each time the shooting, involving Kalashnikovs and other military grade rifles, begins.

AFP has investigated the stories of those caught in the middle, like 13-year-old schoolgirl Maria Eduarda, in a new multimedia report: "Stray Bullets: violence and broken lives in Rio."

With around 60,000 murders a year, Brazil is among the world's most dangerous countries. Rio, host of the 2016 Olympics, has long been one of the hotspots.

But as AFP's investigation highlights, stray bullet incidents add a cruel twist to the wider crisis.

People are shot outside church, in parks or in restaurants, in daytime or at night. Since the cheap construction of favela houses will not necessarily stop a bullet, even staying at home can be dangerous.

Official figures for stray bullets are not released, but reports of incidents come in steadily. A count by Globo newspaper found that 632 people were shot by stray bullets in Rio state, at least 67 of them killed, in the first half of 2017 alone.

- 'So much blood' -

For Maria Eduarda Alves da Conceicao, sudden death came at the northern Rio school where she was known as a diligent student and mad keen basketball player. In a tough city, she was doing everything right.

On March 30, though, everything went wrong.

Just outside her school gates, police with automatic rifles were firing on drug dealer suspects.

It was the type of violent operation that would make top news in many cities around the world but is so common in Rio that it passes largely unnoticed.

One burst of bullets tore past the school fence, hitting Maria Eduarda as she went to fetch water during gym class.

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The police officers almost certainly didn't realize what had happened. They were busy wrapping up their operation outside: on a bystander's cellphone footage, they can be seen executing two apparently wounded suspects on the sidewalk in an almost casual manner.

Inside, Maria Eduarda already lay dead.

"I hugged and hugged her," the girl's mother Rosilene Alves Ferreira told AFP, recalling her arrival at the scene shortly after the tragedy.

"She was still all warm. I hugged her and there was so much blood," said the 53-year-old mother, creases of worry etched across her forehead. "Two of the bullets had hit her little head."

- 'Logic of death' -

Despite the lack of transparency on overall stray bullet casualties, an NGO called Rio de Paz (Rio of Peace) has kept a careful count of child victims since 2007.

In just over a decade, the toll is 42 killed, including babies, toddlers and adolescents. Some died in the family car, some playing football, or while asleep.

The rate is rocketing: 10 children died in 2016 and 10 so far this year, a steady increase on the seven slain in 2015, and a huge jump from the combined total of 10 in the five previous years.

Antonio Carlos Costa, founder of Rio de Paz, says the combination of dense populations, powerful rifles and ceaseless turf wars between different drug factions makes a lethal cocktail in the favelas.

But he reserves his harshest criticism for the police, who treat the areas as war zones.

"Police operations follow the logic of death, the logic of shooting first and finding out who it was afterward," Costa said. "They've lost sight of the risks they impose on civilians."

The police answer that ruthless drug traffickers, ruling entire neighborhoods at the point of a gun, are to blame. So far this year, 126 officers have been killed in Rio state this year, so they have reason to feel they are in a war.

Police are also hampered by funding problems and falling morale in the wake of the Olympics spending splurge.

But while the debate about what needs changing goes on, the likes of Maria Eduarda are likely to keep getting maimed or killed.

"I know they didn't target Maria, they didn't want to kill her, but they were reckless," her mother said.

"They killed her. Although they saw a school there, they still let off more than 60 shots."

AFP's investigation "Stray Bullets: violence and broken lives in Rio" looks at eight cases, including children, a university student and a kindergarten employee.

The report can be seen here: https://interactive.afp.com/Balas-perdidas_253