Colombian authorities on Tuesday arrested three suspects in last week's murder of a U.S. Drug Enforcement Administration agent, police sources told Efe.

Operations are continuing in the capital and in other parts of the country because, according to the source, new arrests are expected.

One of those arrested appears to be the driver of the taxi in which James "Terry" Watson was traveling through an exclusive sector of northern Bogota when two men entered the vehicle allegedly to rob him, but then stabbed him several times, killing him.

Two of the arrests were made in Bogota, while the third was made in Guamo, located some 165 kilometers (102 miles) from the capital.

Authorities suspect that those responsible for Watson's death belong to a gang of robbers of taxis who perpetrate so-called "millionaire outings" during which they rob the rider of his belongings and force him to withdraw money from his bank account at various ATMs.

The initial investigation into those responsible for the murder indicate that they could belong to a Bogota gang called Los Canarios.

Another line of investigation is not ruling out that the killing could have been carried out in of revenge for the investigations into drug trafficking that Watson had been pursuing for three years from the DEA office in Cartagena.

Watson, who recently married a Colombian woman, was in Bogota on business and on Thursday met with officials from other embassies to watch Game 7 of the NBA Final on television. EFE