Colombia's human rights record is facing increasing criticism following the killings of civilians presented by the military as gunmen killed in combat. The case has prompted President Alvaro Uribe to sack 27 soldiers, including three generals and 11 colonels. The BBC's Jeremy McDermott in Bogota reports.
President Uribe ordered a relentless military offensive against rebels
The details of the army investigation into the killing of 11 young men from the slums of Bogota have not been published.
But it appears that the victims, aged between 17 and 32, were lured with false job offers to the province of Norte de Santander by the Venezuelan border.
They were then murdered and presented by the army as paramilitaries killed in combat with troops.
"These discoveries show that in some cases there has been negligence that has permitted that some people could be implicated in crimes resulting from a conspiracy between criminals and members of the army," President Uribe said.
Information suggests that soldiers were working with a paramilitary group involved in drugs trafficking.
Fearing exposure, they allegedly decided to kill civilians and then present them as paramilitaries so that they could pretend they were fighting, not supporting, the drugs traffickers.
Yet this is not just an isolated incident of what is now known in Colombia as "false positives".
There are more than 2,300 members of the security forces or state functionaries under investigation for extrajudicial killings, in which innocents were killed then dressed up, usually as rebels, and presented as having been killed in combat.
Some 535 cases have been registered over the last 18 months, spread across the country.
Such is the pressure for results under President Uribe's "Democratic Security" policy, some military officers will go to extreme lengths to show results and gain promotion.
"This was the right thing for the government to do, sacking all these soldiers," said Maria Victoria Llorente, director of the Bogota think tank Foundation Ideas for Peace.
"However, the question is how far are these investigations going towards rooting out what appears to be a more widespread problem?"
The military has had a string of successes against the warring factions, particularly against the largest rebel group, the Revolutionary Armed Forces of Colombia (Farc).
These successes have given Mr Uribe unprecedented levels of support.
Mr Uribe, whose father was killed in a botched kidnapping attempt, has ordered the military to launch relentless offensives against the rebels.
His crowning moment was in July this year when 15 hostages - among them French-Colombian politician Ingrid Betancourt - were freed from Farc's clutches after undercover intelligence officers persuaded a guerrilla commander to deliver his hostages to an "international humanitarian mission".
This makes the abuse of human rights by the military all the more dangerous for the president as it challenges the very legitimacy of his policies and his government.
11 young men disappeared from poor Bogota suburb in early 2008
Their bodies were found in mass graves near Venezuelan border in August and September
Rights groups accuse the army of killing civilians to inflate successes
More sackings are expected. Perhaps the head of the army, Mario Montoya, will be the next casualty as he has been accused of once supporting the illegal paramilitary army, the now demobilised United Self-Defence Forces of Colombia (AUC).
Mr Uribe has come under intense criticism on the subject of human rights, with both Human Rights Watch and Amnesty International publishing condemning reports this month.
This mounting pressure might also affect Bogota's closest ally, the US. Washington and the Bush administration continue to grant Colombia some $600m (£371m) in aid every year.
There have, however, been instances when parts of this aid have been blocked or delayed because of human rights abuses.
President Bush has also been unable to get a free trade agreement through the US Congress for Colombia.
One of the reasons the Democrats have given is that trade union workers are still killed with frightening regularity and with a great deal of impunity.
This latest scandal is likely to make whoever wins the US presidential race think twice before continuing aid, much of it military, at current levels.