This article is the third in a series by Human Rights Watch to mark the 10 years since the Soacha cases.

Many in Colombia associate General Mario Montoya Uribe with the “false positive” killings committed when he was the head of the army.

Army brigades across Colombia systematically murdered thousands of civilians. The victims, recorded as enemies killed in combat, came to be known as “false positives.” Such cases peaked under Montoya’s command, which lasted from February 2006 through November 2008.

But allegations of false positives associated with units Montoya commanded go way back. The report on false positives the Attorney General’s Office submitted in June to the Special Jurisdiction for Peace –the judicial system created as part of a peace accord with the FARC– makes it clear.

The death of Henry Palencia Antúnez, a farmer, in Zulia, Norte de Santander, on October 14, 1992, was one of the first of these killings, the report says. Troops of Cavalry Group No. 5—named for the War of Independence hero General Hermógenes Maza—murdered Palencia Antúnez and reported him as a member of the Army of National Liberation (ELN) killed in combat.

In 2011, two soldiers were convicted for the killing, after confessing. A detail that jumps out from the Attorney General’s Office report is that the commander of Cavalry Group No. 5—the man who signed the order for that particular operation—was then-lieutenant colonel Mario Montoya (see document).

“False positives” became pervasive 10 years later, in 2002. But at the beginning of that period, from 2002 through 2005, the report says that they were “concentrated,” among others, in the army’s 1st division (see document). Montoya commanded the 4th brigade, which then belonged to the 1st division, from December 2001 to December 2003. As Human Rights Watch has shown, prosecutors have opened investigations into at least 44 killings by 4th brigade troops during that period.

In December 2003, Montoya became commander of the entire 1st division—a position he held until April 2005. The number of people murdered by troops of the 1st division departs from the “national norm,” the report says. While the 1st division shows a “significant number” of false positive murders before 2005, other units do not show a striking increase until the beginning of 2006 (see document).

A large portion of those early, 1st division murders, the report shows, were committed in collusion with paramilitary death squads (see document). In a macabre marketplace, army units seem to have traded guns for victims. The report puts it this way: “Apparently in exchange” for the victims, soldiers “provided weapons” to the death quads and “tolerated their criminal activities.”

In April 2005, Montoya became commander of the Joint Caribbean Command—a new special unit with jurisdiction over the entire northern coast of Colombia, as well as the Antioquia and Chocó departments. According to Attorney General’s Office data Human Rights Watch has reviewed, prosecutors have opened investigations into possible extrajudicial executions committed by many of the unit’s brigades—the 2nd, 4th, 10th, 11th, and 17th— – during Montoya’s command. The worst appears to be the 4th brigade, which operated in Antioquia. Prosecutors have opened investigations into 81 alleged extrajudicial executions committed in 2005 by the 4th brigade, according to a 2016 Attorney General’s report (see document).

In February 2006, Montoya became the head of the army, and that year false positives army-wide began to soar. The 2nd, 3rd, 5th and 6th divisions had relatively few investigations for killings between 2002 and 2005, the report says, but cases significantly increased since 2006.

In 2006, the number of cases army-wide doubled from the previous year, the report shows, with 470 alleged false positives. The figures climbed dramatically again in 2007, to 733 cases (see document). And the change was more than a matter of numbers: a new modus operandi emerged under Montoya’s watch.

Starting in early 2006, the behavior of military units “mutated,” as the report puts it. Even as the bizarre killings spread to new battalions—and new municipalities—the methods of acquiring victims altered. Many victims were now lured—sometimes by bogus job offers—to accept transport from urban areas to fields in remote corners of Colombia, where, they were murdered and reported as enemies killed in combat (see document).

The number of victims who were farmers decreased, as the report puts it, while an “urban population dedicated to informal labor” became the “most representative type of victim.” The best-known examples are the “Soacha cases.”

Soacha, a Bogota suburb, was home to more than a dozen teenagers and young men whose bodies turned up, in mid-2008, more than 600 kilometers away, in Norte de Santander Province.

The Soacha scandal was big enough to halt the army’s systemic false positive killings. The government dismissed 27 army officers and soldiers and created a special army unit to investigate false-positive cases. Montoya resigned right afterward, in November 2008. The number of false positive cases reported in 2009 dropped to levels last seen in 2001, the Attorney General’s Office notes: fewer than dozen a year.

Montoya, who is currently facing investigation for false positives, has told prosecutors that he strove to prevent his troops from killing civilians. If he tried to prevent these atrocious crimes, why were so many of his units involved?