Hello and welcome to the witness history podcast from the BBC World Service with me, Ben Henderson.

It's 2008 and we're in Colombia.

A civil war has been raging for more than 40 years between the government and two left-wing rebel groups,

called the National Liberation Army and the revolutionary armed forces of Colombia, known as the FARC.

The bodies of 22 civilians are found in the countryside.

They'd been recruited by the army for what seemed like legitimate jobs.

But when they turned up for work, they were executed and their corpses were dressed to look like they were rebels killed in battle.

Thousands of civilians were murdered like this. It became known as the false positive scandal.

When I was walking up to the place where the graves were, I saw the faces of many men, women and children on the side of the road, as if they were giving us a guard of honor.

This is Jacqueline Castillo. Her brother Jaime was one of the victims.

And we get the impression that these people knew of the terrible crimes that had happened here.

It almost seemed like they were the lost souls of those who had been killed.

But why did the military kill innocent civilians and make it look like they'd died in battle?

Well, there are accounts of false positive killings going back to the 1980s, but they peaked between 2002 and 2008 under the presidency of Alvaro Uribe.

Desperate to show they were winning the war, his government heavily incentivized troops to kill as many rebels as possible.

A military unit racking up kills was rewarded with promotions and extra holiday.

The problem was, killing rebels was extremely dangerous, so some military units found an easier alternative.

Luring vulnerable people like drug addicts, the unemployed, or people with learning difficulties out to the countryside with the promise of jobs, and then killing them.

Jacqueline's brother was one of those people.

Since he was at school, my brother Jaime had addiction problems, but it was when our mother died that his addiction got worse.

And as a result, he ended up living on the street.

And it was those kind of people that the soldiers prayed on.

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