Human remains were pulled from at least four mass graves Sunday in the same area where 43 students went missing after a police shooting in the southern state of Guerrero, Mexico.
If the burned bodies that have been found in the mass graves since Saturday are confirmed to be the normalista teaching students missing since the September 26 shooting incidents, the discovery would be one of the worst massacres in recent history in Mexico.
Mexican army and naval forces secured the grave sites as forensics investigators began removing what were reportedly at least nine charred bodies, possibly up to 20. Authorities said they could not yet determine the number of victims buried in the sites in the municipality of Iguala, a small city in the volatile mountainous region of the state where the chaotic shooting incidents occurred last week.
The discovery is the latest grim turn in a case that points to the deep infiltration of criminal gangs in the ranks of Mexico's municipal police departments, and the critical levels of narco and political violence that make Guerrero one of the country's deadliest states.
Authorities in Mexico City also said they are investigating the case. "The Mexican state will not allow an act as egregious as this to go unpunished," chief federal criminal investigator Tomás Zerón said Saturday.
In Guerrero, two criminal gangs that didn't even exist less than five years ago — the Guerreros Unidos and Los Rojos — are the main suspects in the disappearance of the 43 teachings students in Iguala, federal sources and authorities said in Mexico.
Thirty people are under arrest in connection to the shooting, including at least 22 Iguala police officers, authorities said Saturday. The police force in Iguala is believed to be heavily tied to the cartels. The mayor of Iguala, Jose Luis Abarca, is wanted for questioning and has been missing since the shootings.
Guerrero authorities have stopped short of saying the bodies being pulled this weekend from the graves in the forested hillsides around Iguala are the missing students, saying they would wait for the results of DNA testing.
But state prosecutor Iñaky Blanco Cabrera said the detained Iguala officers are the suspects in last week's six shooting deaths, and that the information the officers provided under interrogation led them to the mass grave sites in Iguala.
"I call on every political, social, economic force in our state: No to confrontation," Guerrero governor Angel Aguirre said during Saturday's press conference. "Guerrero today needs us all."
Meanwhile, parents and relatives of the missing students protested in the state capital of Chilpancingo, blocking roads and calling on authorities to locate and turn over the students alive. Normalistas across the state called for a "national march" Wednesday to protest the disappearances.
The country in recent days has also been absorbing the aftermath of a separate massacre in the neighboring state of Mexico, in which 22 suspected cartel members were allegedly executed by Mexican soldiers. Authorities have detained eight servicemen, and have so far charged three with homicide and other crimes.
VICE News contributors Melissa del Pozo in Iguala and Marisol Wences in Acapulco contributed to this report.
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