Riot Between Los Zetas and Rival Gang Kill 49 In Mexican Prison

An inmate shouts and makes a hand sign from behind his barred window at the Topo Chico prison, after a riot broke out around midnight in Monterrey, Mexico, Thursday, Feb. 11, 2016. Dozens of inmates were killed and several injured in a brutal fight between two rival factions at the prison in northern Mexico, according to the state governor. AP Photo/Emilio Vazquez

MONTERREY, Mexico—A prison riot that left 49 inmates hacked, beaten or burned to death opened searing questions about gang rule, extortion and human rights violations in Mexico’s overcrowded prisons, where people merely awaiting trial are mixed in with some of the world’s most hardened killers.

Those questions were not abstract for Victoria Casas Gutierrez, a cleaning lady who had waited for hours Thursday for news of her 21-year-old son, Santiago Garza Casas, who was facing trial for allegedly acting as a lookout for a criminal gang.

Santiago was sent to the Topo Chico prison in September for missing a parole appointment. He was immediately mixed in with a prison population that included murderers.

They charge taxes, and if the relatives don't bring a certain amount ... they beat them.