A former army officer serving a prison sentence for the 1998 killing of a Roman Catholic bishop died in a jail riot that killed a total of five inmates Monday, Guatemalan authorities said.

Byron Lima was convicted of the murder of Bishop Juan Jose Gerardi, who was an outspoken critic of military abuses during the country's 36-year civil war. The death was confirmed by firefighter Julio Sanchez, but no other details were released.

Lima was an army captain in 2001 when he was sentenced to 30 years for the killing. The term was later reduced to 20 years. Three other men were also convicted in the case, including Lima's father.

Lima had been considered the most powerful inmate in Guatemala's prison system. He was facing additional charges for his activities behind bars.