Colombian authorities are investigating an American coal mining company for allegedly financing a paramilitary group during the South American nation's bloody civil conflict.

Prosecutors are looking into whether Alabama-based Drummond Co. Inc. made irregular payments to a contractor, Jose Blanco, who was convicted in 2013 in the killing of two union leaders who worked at Drummond.   Blanco was sentenced to 38 years in prison.

Drummond has been exporting coal out of Colombia for seven decades, and allegations that the company financed paramilitary death squads to silence union activists and suspected leftists have been around for decades as well.  But when the families tried to seek justice in the US courts, they were turned back by rulings in favor of the company.

Other US companies have admitted paying paramilitaries.  In 2007, Chiquita Brands International pleaded guilty to right-wing militias in 2007, clai mingit was extorted and paid out of fear of violent retaliation.