Guatemala's top anti-drug investigator, Adan Castillo, has been charged in the US with drug-trafficking.
Mr Castillo, who is accused of conspiring to import and distribute cocaine in the US, was detained after arriving in the country.
His deputy and another investigator were also arrested and indicted.
The US Drug Enforcement Administration said the arrests followed a four-month investigation in the United States and Central America.
Mr Castillo was in the US state of Virginia for a training course on how to fight drug trafficking through ports when he was arrested, Guatemalan Interior Minister Carlos Vielman said.
The arrests were "a strong blow to the infiltration of organised crime in the structures of the Guatemalan government", Mr Vielman said at a news conference in Guatemala City.
US officials confirmed the arrest.
In a recent interview with the Associated Press, Mr Castillo said he was frustrated in his job because corruption in the Guatemalan government made fighting drug smugglers impossible, and that he was ready to quit after just six months in his post.
Guatemala is a major staging post for cocaine that is trafficked from Colombia to the US.
US officials believe 75% of the cocaine that arrives in the US travels through Guatemala.