GUATEMALA CITY - Guatemala's police chief and top anti-drug officer were arrested Tuesday for suspected links to drug traffickers and the murder of five policemen, an official source told AFP.

Police chief Baltazar Gomez and anti-drug division head Nelly Bonilla were arrested Tuesday during an "investigation into a drug robbery (in April 2009) in Amatitlan, which those detained today are believed to have participated in," said Attorney General Amilcar Velasquez.

Five law enforcement officers were killed during the robbery, he told reporters.

The arrests were a blow to organized crime in Guatemala and its efforts to infiltrate government institutions, Velasquez said.

"We're doing all we can to dismantle organized crime's operations within state institutions, and the CICIG help in this has been invaluable," the official added.

The investigation was carried out jointly by police and the United Nations-backed International Anti-Impunity Committee of Guatemala (CICIG), Velasquez said.

Gomez was apprehended at the police's anti-corruption headquarters, as he was about to testify in an investigation into a 6.5 million dollar fuel-buying scam involving the police and the Interior Ministry.

Gomez and Bonilla are facing charges of conspiracy, breaking and entering, abuse of power, making illegal arrests, drug trafficking, obstruction of justice, illegal possession of firearms and ammunition.

Velasquez said that including Tuesday's arrests, 15 people have been apprehended in the drug robbery investigation -- the other 13 were also members of the police's anti-drug trafficking division.