Soldiers take part in a ceremony at the Jose Maria Cordoba military school in Bogota on June 3. (Guillermo Legaria/AFP/Getty Images)

In a twisted attempt to show battlefield success against FARC rebels, the Colombian military killed hundreds, possibly thousands, of civilians between 2002 and 2008, falsely depicting them as slain combatants, according to a new report by Human Rights Watch.

The killings, known as “false positives,” were the source of a huge scandal in 2008, but the new report alleges that the practice was far more extensive and systematic than previously known. Many of Colombia's highest-ranking military officials either condoned the practice or did nothing to stop it, according to the rights group.

“Under pressure from superiors to show ‘positive’ results and boost body counts in their war against guerrillas, soldiers and officers abducted victims or lured them to remote locations under false pretenses — such as with promises of work — killed them, placed weapons on their lifeless bodies, and then reported them as enemy combatants killed in action,” the report states.

The killings amount to “one of the worst episodes of mass atrocity in the Western Hemisphere in recent decades,” according to the group.

An advance copy of the report was provided to The Washington Post. Human Rights Watch investigators said they would announce their findings Wednesday in Bogota and present them to President Juan Manuel Santos, who is attempting to negotiate a peace agreement with the Revolutionary Armed Forces of Colombia, or FARC, to end the hemisphere’s longest-running civil conflict.

Members of the FARC-EP leftist guerrilla delegation arrive at the Convention Palace in Havana on Tuesday for peace talks with the Colombian government. (Yamil Lage/AFP/Getty Images)

The report comes at a time of flagging public support for the peace negotiations, now in their third year, taking place in Havana. The talks have made more progress than any previous attempt at armistice, but the two sides have yet to resolve key issues related to troop demobilization and what punishment, if any, the insurgents will face.

False-positive killings allegedly peaked during the period described in the report, when then-President Álvaro Uribe escalated the fight against FARC and took back large swaths of rebel-held territory. Santos served as defense secretary under Uribe between 2006 and 2009, but the two men are now political archrivals.

During that time, commanding officers placed heavy emphasis on “combat kills” as a measure of military success, the report says, in some cases rewarding troops with cash payments and vacation time.

Soldiers abducted rural peasants, drug addicts, the homeless and petty criminals, killing them and dressing them in combat fatigues, then filling out bogus battlefield reports to pad fatality numbers.

“What makes these crimes unique is that they were not about eliminating political opponents or supposed guerrilla sympathizers; they were basically about killing civilians just to boost body count stats in the war on guerrillas,” said José Miguel Vivanco, Americas director for Human Rights Watch.

“What this says about the conflict is that impunity has become so cemented in Colombia that the army believed it could get away with flagrant and systematic murder on a large scale,” he said. “Army officers clearly felt emboldened to kill civilians without any consequences.”

The killings have subsided since 2008, when the false-positives scandal erupted after the abduction and killing of 19 young men from a Bogota slum. The army’s top commander was forced to resign, and three army generals and nearly a dozen officers were fired. Santos, then defense secretary, pledged to investigate.

But the Human Rights Watch report says other military officers have been promoted since, despite evidence of extrajudicial killings under their command. Colombian prosecutors are investigating more than 3,000 allegations of false-positive killings, the report said. Although about 800 soldiers have been charged, most of them are lower-ranking.

The report notes that the current head of Colombia’s armed forces and the top army official formerly led brigades that are alleged to have committed dozens of extrajudicial killings.

Sen. Patrick J. Leahy (D-Vt.), a longtime critic of U.S. military aid flowing to Colombia despite evidence of rights violations, said that he was “deeply troubled” by the report and that it should force a new look at U.S. security assistance.

“As we provided billions of dollars in aid to the Colombian army over many years, its troops systematically executed civilians,” Leahy said in a statement to The Post.

“We have supported the Colombian military because the country has been threatened by an insurgency,” he said. “But unless Colombia’s military leaders are people of integrity, it will be difficult to continue to support an institution that engaged with impunity in a pattern of gross violations of human rights.”

The report urges Santos and his government to do more to protect witnesses testifying in false positive cases, assign more prosecutors to investigate them and go after higher-ranking officers who may bear responsibility, among other measures.

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