One of Colombia’s most powerful paramilitary leaders has been condemned by a Miami court to 33 years in prison, convicted of “leading an international drug trafficking ring which backed a terrorist organization.”

Carlos Mario Jimenez, better known by his alias “Macaco” was perhaps the most powerful commander in the United Self-Defense Forces of Colombia (AUC). He led the Central Bolívar Bloc of the paramilitary army, which demobilized more than 5000 fighters during the peace process with the government. The AUC was on the U.S. list of terrorist organizations.

While Jimenez turned himself in as part of the government’s amnesty legislation, the Peace and Justice Law, it was determined that he continued to run his drug trafficking empire while in prison, and therefore was not eligible for its benefits. He was considered so dangerous, that in the lead up to his extradition in 2008 he was kept not in a maximum security prison, but aboard a Colombian frigate on the high seas.

The drug trafficking networks, and much of the territory that Jimenez controlled, are mainly under the control of the Rastrojos, now one of Colombia’s most powerful transnational criminal organizations.

Jeremy McDermott is co-founder and co-director of InSight Crime. McDermott has more than two decades of experience reporting from around Latin America. He is a former British Army officer, who saw active...