The fighting occurred about 160 miles northeast of the capital, near the city of Bucaramanga.
The judge who was killed, 29-year-old Samuel Alfonso Rodriguez, was driving a car accompanied by his wife when he was shot to death in the northeastern city of Bucaramanga, police said in a communique broadcast by the RCN radio network.
The two were arrested Oct. 20 by Colombian authorities in Bucaramanga on federal drug trafficking charges steming from a 1988 indictment returned by a federal grand jury in Greensboro, N.C.
Yanine Daz, commander of the army's Second Division, said from Bucaramanga that the guerrillas belonged to the Revoloutionary Armed Forces of Colombia, or FARC, a communist group.