U.S. authorities on Monday revealed an investigation into the former commander of the Colombian Police’s anti-narcotics unit who, according to testimony, worked with crime syndicate “Oficina de Envigado.”

According to the testimony of Felix Isaza, alias “Beto,” a former member of the Medellin-based drug trafficking organization, General Cesar Augusto Pinzon maintained contact with top ranking members of the Oficina and was paid large sums of money from the group.

He also alleged to U.S. investigators from the Drug Enforcement Administration (DEA) and Immigration and Customs Enforcement that Pinzon had ties with the Cali and Valle del Norte drug cartels.

Extradited former AUC leader Carlos Mario Jimenez, alias “Macaco,” told officials that the retired general “was a corrupt official” who was responsible for the killing of 14 people in the 1990s at a Medellin restaurant during a police operation aimed at capturing two lieutenants from late drug lord Pablo Escobar’s Medellin Cartel.

Macaco also alleged that Pinzon formed a group called “La Grua,” aimed at eliminating suspecting informants that could testify against corrupt officers. According to DEA investigators, the group burned “people in acid” and is suspected of killing an estimated 20 people in five years.

The allegations come on the heels of a U.S. investigation against retired police and former President Alvaro Uribe’s security chief, General Mauricio Santoyo who was charged with drug trafficking June 16. He is suspected of collaborating with the Oficina de Envigado and the AUC between 2000 and 2008.

From Colombia Reports