GUATEMALA CITY, Guatemala (AFP) — Thirteen people were killed Monday in a prison riot in Guatemala, among them an ex-soldier imprisoned for killing a Roman Catholic bishop almost two decades ago, according to Guatemalan authorities.

“Among the dead is Mr (Byron) Lima,” who was convicted for his role in the 1998 murder of Juan Gerardi, and died during a “brawl” among inmates, Interior Minister Francisco Rivas told reporters. A previous toll had just two dead.

The clash took place inside Pavon prison, just outside the capital, after authorities tossed a grenade at the inmate’s “security detail.”

Rivas said the deadly uprising was linked to Guatemalan drug lord Marvin Montiel Marin, alias “El Taquero,” who has been in the same prison for the 2008 killings of 15 Nicaraguans and a Dutch national.

The bishop had investigated atrocities committed during Guatemala’s civil war, documenting more than 50,000 human rights violations — most attributed to the army — during the 1960-1996 armed conflict.

Lima was serving a 20-year prison sentence handed down in 2001. Three others, including his father, a former colonel, were convicted over the bishop’s murder.

While serving his sentence, Lima was considered one of the most powerful figures inside Guatemala’s prison system.

In 2014, a judge charged Lima with leading a criminal network that effectively controlled prison life, including arranging inmate transfers, conjugal visits and access to phones.