Police officers in Mexico accidentally stumbled upon 150 skulls of those they thought were murder victims. It turns out they were part of a cold case, but one that stretches back about 1,000 years. 

On Wednesday, National Institute of Anthropology and History (INAH) in Mexico City announced that the skulls actually belonged to victims who were decapitated between the years 900 A.D and 1200 A.D, who were sacrificed as part of a ritual. What shed light on the skulls’ origins was the presence of wood fragments that were consistent with another Aztec practice of stacking human skulls atop a rack known as a “tzompantli”. 

According to the Smithsonian, tzompantli were used to publicly display the skulls of war prisoners and sacrificial victims alike. They were mentioned centuries ago in the writings of Spanish conquistadors and mounds have been discovered by archaeologists in recent decades.

Javier Montes de Paz, a physical anthropologist at INAH who examined the skulls, said that the presence of wood and the lack of any bores in the temporal regions of the bones points to the likelihood that they were stored in a tzompantli than part of a spiritual sacrifice. In those instances, a bore was bashed into the front of the skull after the ritual before being strung up on a wooden pole.  

Their finding provides answers in a case that began over a decade ago in 2012.

In that year, police officers in the small town of Frontera Comalapa along the border with Guatemala came across the remains of what they assumed were murder victims in a region rife with violence and trafficking. 

Regions of Mexico have been saddled with high levels of violence that have gone largely unaddressed for years. According to the Mexican National Statistics Institute, about 36,579 murders took place in Mexico in 2020 alone. In a separate analysis by a Mexican think tank, it was found that up to 94.8% of cases of violence go unpunished and about 93.3% of cases are not reported to police.