On Tuesday, Mexican authorities found remains in the municipality of Chilapa de Alvarez, located in the southern state of Guerrero.
Some of the bodies were found with their hands tied and signs of torture, while the 11 heads were uncovered in four black plastic bags.
Guerrero made headlines in September when 43 students from the Raúl Isidro Burgos Rural Teachers' College went missing.
In December the burnt remains of student, Alexander Mora Venancio were discovered. Venancio is the only missing student who has been identified.
On Wednesday, state prosecutor, Miguel Angel Godinez Munoz, announced that there were 6 sites under investigation.
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