BOGOTA (Reuters) - Eight current and former officials of U.S. coal producer Drummond Co Inc [DRMND.UL] were called last week to testify before Colombian investigators about allegations the company supported far-right paramilitary death squads, a source from the attorney general’s office said on Tuesday.

Prosecutors have investigated allegations for more than a decade that Drummond financed paramilitary groups involved in the 2001 assassination of two union leaders in northern Colombia.

Drummond and company officials were exonerated by U.S. courts in the case. In Colombia officials were also exonerated, but a contractor was sentenced to 38 years in prison for making payments to the paramilitaries.

The source in the attorney general’s office would not confirm whether this investigation relates to new allegations or if it is part of an open investigation into the previous charges. The official would also not confirm whether the investigation is based on new witness testimony.

Drummond lawyer Jaime Bernal Cuellar said company officials are willing to speak to investigators. He said untruthful witnesses have testified against the company in the past.

“I think it’s about investigating the possible relations of the Drummond directors with the paramilitary groups, so I think they are the same tests and the same facts, I do not know if they have new elements,” Bernal Cuellar said. “These facts have been investigated in the United States and Colombia on several occasions and they have acquitted the directors they thought they could link in. There are no links, it has been shown that Drummond did not collaborate or pay paramilitary groups, with the exception of the contractor,” Bernal Cuellar said. The current president of Drummond in Colombia, Jose Miguel Linares, former president and current adviser Augusto Jimenez and community relations manager Alfredo Araujo are among those set to be interviewed, the lawyer said. Paramilitary groups emerged in the 1980s, funded by ranchers, landowners, merchants and drug traffickers eager to defend themselves from attacks by leftist guerrilla groups.

Thousands of paramilitary fighters demobilized a decade ago under a peace deal, but many more joined crime gangs which continue to terrorize some parts of Colombia with killings, displacements, sexual violence and forced recruitment.

More than 260,000 people have been killed during Colombia’s five-decade-long war. Drummond produces coal in the open pit mines of Pribbenow and El Descanso in the department of Cesar in northern Colombia. The company produced 32.4 million tons of coal in 2017 and exported 32.3 million tons from Colombia.