A former commander of Bolivia's anti-narcotics police force has been arrested in Panama on charges of drugs trafficking, Bolivian authorities say.
Gen Rene Sanabria was immediately transferred to the US to face trial.
Bolivia has arrested three other senior police officers suspected of helping him smuggle cocaine to the US.
Gen Sanabria was head of Bolivia's anti-drug agency until 2009, and was still working as an intelligence adviser to the government.
Bolivian Interior Minister Sacha Llorenti said Gen Sanabria was suspected of travelling to Panama to organise further shipments of cocaine to the US, after allegedly despatching 144kg (317lbs) of the drug last November.
He said Bolivia expected to receive details of the charges against him from the US on Monday, and did not rule out asking for his extradition.
Gen Sanabria was arrested on arrival in Panama on Thursday, but this was not made public by the Panamanian or US authorities.
Correspondents say the arrest is an embarrassment for the government of Bolivian President Evo Morales, which has been defending itself from US allegations that it is not doing enough to stop the production and export of cocaine.
In 2008 President Evo Morales expelled the US Drug Enforcement Agency from Bolivia, accusing it of supporting opposition movements.
Along with Venezuela and Burma, Bolivia is on a US list of countries that are failing to meet their obligations under international counter narcotics agreements.
After Peru and Colombia, Bolivia is the world's third largest producer of coca - the raw material for cocaine.
President Morales is himself a former coca grower, and has defended the use of the leaf for traditional medicinal purposes, while insisting his government is doing all it can to stop illegal cocaine production.