Some 25 kilograms of marijuana were discovered on a military plane after it landed at an air base in central Colombia, raising questions about the extent of the the armed forces’ involvement in the drug trade.

On December 13, the Colombian military released a statement confirming reports that the drug shipment had been found on an air force plane, calling it “a shameful situation.”  According to officials, the drugs had been smuggled by members of the army’s 17th Brigade, stationed in the turbulent southern province of Cauca.

The individuals in question have been arrested, and the army has said it will launch a full investigation into the incident.

Cauca has emerged as the heartland of marijuana cultivation in Colombia, with police estimating that some 95 percent of all marijuana seized in the country is either grown in or trafficked through the province.

The discovery of the illegal cargo comes at a time when the involvement of the military in drug trafficking is under scrutiny, after a former head of the country’s military intelligence agency — who also at one time headed the 17th Brigade — was convicted early this month of drug trafficking ties and sentenced to 13 years in prison.

Another recent case of high-level corruption among the country’s security forces is that of police General Mauricio Santoyo, who has admitted to working with paramilitary organizations during his time as head of security under former President Alvaro Uribe.

While the Colombian armed forces have a reputation as being more reliable than the police force, the latest arrest calls this into question. Nevertheless, the involvement of the Colombian military in the illegal drug trade is still far less than in neighboring Venezuela, where high-level military commanders are believed to facilitate drug shipments in and out of the country.