BOGOTA, COLOMBIA — A feared paramilitary boss has been charged with ordering the murders of two union leaders at a coal mine owned by Drummond Co. Inc., an Alabama company being sued in a U.S. court for alleged complicity in the killings.

Rodrigo Tovar Pupo, better known as "Jorge 40," is accused of ordering hit men to kill the two men, the federal prosecutor's office said Thursday.

Former Colombian federal intelligence official Rafael Garcia has said he witnessed the president of Drummond's Colombian subsidiary deliver a briefcase full of money to paramilitaries led by Tovar to pay for the murders.

Drummond officials deny any involvement in the killings or ties to the far-right militias, and the Birmingham, Ala.-based company is not facing criminal charges in Colombia.

A trial of Drummond for alleged involvement in the murders of Victor Orcosia and Valmore Locarno and a third worker is set for July 9 in a U.S. federal court in Birmingham.

Tovar is imprisoned as part of a peace deal with the government, under which some 31,000 paramilitary fighters have disarmed. In exchange for confessing to crimes, the paramilitary bosses are to receive prison sentences of no more than eight years.

Tovar has not acknowledged involvement in the Drummond killings, a spokesman for the chief federal prosecutor's office said on condition of anonymity.

A U.S. congressman has pledged to hold hearings into the alleged involvement of U.S. multinationals in the murder of labor activists in Colombia. And Colombian President Alvaro Uribe, on Capitol Hill this week to lobby for passage of a free-trade agreement, has faced sharp criticism from congressional Democrats over attacks on union activists.

More than 800 trade unionists have been killed in Colombia in the last six years, according to government figures.