Neiva, Colombia - When the government task force unearthed civilians during the Colombian guerrilla conflict, the government task force dug a large-scale grave and they received some hands-on help from the perpetrators of these war crimes.

In front of Colombia's first, three former Army soldiers wore white protective suits and armed with trowels and buckets, spent 10 days with forensic experts, digging soil, removing bones and clothes, and bagging remains during the war.

"These atrocities should never happen," one of the soldiers said during excavations in the cemetery in the central Colombian city of Neiva.

The soldier was a former lieutenant colonel and asked to be identified only by his name Mario, for fear of revenge. He admitted that in the mid-2000s, soldiers under his command were shot and killed 63 civilians and reported that they were killed in operation.

Mario and other former soldiers participated in the excavation and reached an agreement with the Colombian War Crimes Tribunal, which is also investigating the atrocities of guerrillas, established under the 2016 Peace Treaty, which ended many battles.

The accused former combatants refused to face a 20-year lag behind. But those who acknowledge and compensate – by providing information about the way and why the murder is and where the deceased, conducting social work and apologizing to the relatives of the victim – can avoid jail. Instead, they will receive a five-to-eight-year judgment in what the court calls “restricted freedom,” but it has not been defined.

The former soldier began assisting with the excavation of Neiva last month and will continue to continue in cemeteries across the country, with most of the victims believed to have been buried.

"I think this message is very important because it is the first time Colombia is looking for victims in a cemetery," said Alejandro Ramelli Arteaga, president of the War Crime Tribunal.

Mario, similar to the Vietnam War, said Colombian officers like him were under enormous pressure from top brass to increase the number of people inside. Failure can undermine their careers while complying, which can lead to promotions, additional time off and other allowances.

But the policy has led to massive abuse as soldiers rounded up farmers, unemployed people and even teenagers. The detainees were then executed, dressed in rebel uniforms and reportedly killed, with many buried in anonymous graves in the cemetery.

Mario told NPR: “To show the results, the soldiers caught innocent people and killed them.” When asked about his reaction to the atrocities committed by the troops he commanded, he replied: “It became so common that it seemed almost normal.”

The War Crime Tribunal found that the Army illegally killed more than 6,400 civilians between 2002 and 2008, a huge attack on the rebels by the U.S.-backed Colombian army. Executions, widely known as "false alarms", remain a huge stain on the Army's reputation.

“Of course, this is one of the toughest crimes committed during the armed conflict in Colombia,” former Colombian MP Juanita Goebertus, who participated in peace talks with the guerrillas and now leads the leadership of the Observatory for Human Rights in the Americas.

Now, former soldiers helped to dig, which gave them a clear view of the damage they were doing. In Neiva, they spend up to 10 hours a day in the tropical sun and dirty their hands in the soil of the cemetery as they assist forensic experts. However, their efforts are also a therapy that attempts to make modifications.

“It helped me bring my life together,” said a former soldier who asked to remain anonymous, after opening a firm basement with a hammer and chisel.

The fact that complicates these efforts is that many dead people are simply dumped in a hurry to dig out the cluster of graves without identification. Diego Sevilla, head of the government forensic team in Neiva, pointed to a site at the cemetery that is believed to possess the remains of six people. But his team found 12 skulls, meaning at least 12 people were buried there.

"The bodies are all mixed together," Sevilla said.

Relatives of the victims have been closely monitoring the mining of information that hopes to obtain information about their loved ones. They include Yolanda Rocha, who said her 15-year-old brother was one of the "false alarms" and might have been buried here. She spoke with some former soldiers, who expressed deep regret.

“It’s very difficult,” Rosa said of those encounters. "You want the truth, but you're like opening an old wound."

With the help of former soldiers, similar excavations will soon begin at other Columbian cemeteries. But after 10 days in Neiva, the forensic team ended the first phase of the work by holding a ceremony to commemorate the deceased.

Sevilla, the team leader, recited a poem. Others solemnly placed flowers on bags of remains. Eventually, Mario, a former officer, whose man killed 63 civilians, moved forward.

"Hopefully this will never happen again because the pain this causes is huge," he said.