A riot that broke out at a prison facility in Mexico has left 49 inmates dead and 12 others injured. The violent incident also highlighted the serious issues with the prison's system that previously went unnoticed.

According to officials of the Topo Chico prison in Monterrey, Nuevo Leon, the riot started at around 11:30 p.m. after an inmate started fires in the facility's storage areas. They said it was part of the clash between members of the rival drug cartels Zetas and Gulf, the same groups that waged war against one another in Nuevo Leon from 2010 to 2012, CNN reported.

The two factions were reportedly led by Juan Pedro Zaldivar Farias of the Zetas and Gulf's Jorge Ivan Hernandez Cantu. However, according to Renato Sales Heredia, the commissioner of Mexico's National Security, the riot broke out due to an internal conflict within the Zetas. The official said two groups from the gang were fighting with one another for control of the prison.

The fires were put out around 30 to 40 minutes after they were started but the riots lasted until 1:30 in the morning. After guards had been able to take control of the facility, they discovered that almost 50 people have already died. Officials noted that during the fights, inmates used various improvised weapons. Many of those who died were beaten or burned to death.

After hearing about the incident, relatives of the inmates flocked to the prison to check if their loved ones were included in the death toll. Although 40 of the killed inmates were already named, officials are still trying to identify the remaining nine since their bodies are too burnt to recognize.

As for the inmates who survived, their relatives said that they are afraid to talk about what happened. They said that many of them have been threatened to prevent them from discussing the incident, according to The Washington Post.

The riot at the Topo Chico prison angered relatives of the inmates as it displayed the current condition inside the facility. Aside from issues about overcrowding, another problem plaguing the facility is the number of cartel members being held inside. Many of them, despite being imprisoned, still have access to their gangs and can even bring in drugs, guns and other weapons inside the facility.

Also, as noted by some of the inmates' relatives, the prison also serves as a holding facility for individuals who are only awaiting trial. Because of this, these people get mixed with criminals convicted of heinous crimes.