El Trocs Cave (pictured above) is nestled in a serene, picturesque part of the Pyrenees Mountains in Spain, but 7,300 years ago, the area's tranquility was shattered by gruesome violence. Five adults and four children between the ages of three and seven were brutally murdered around 5300 BCE. Their skeletal remains were recently discovered and analyzed by an international team of researchers.

"The violent events in Els Trocs are without parallel either in Spain or in the rest of Europe at that time," the team reported in the journal Scientific Reports.

"The adults display consistent arrow-shot injuries to the skull but not to the perpendicular skeleton. The children and adults furthermore show traces of similar blunt violence to the skull and entire skeleton."

In short, these people were shot, struck, and hacked to death, a terrible truth evinced in their beaten and broken bones.

Who were these people? Who killed them? And why? Separated from the heinous event by thousands of years, it may be impossible to ever know for sure, but the researchers have a few ideas.

Agriculture and agrarian societies were starting to spring up around this time, so it's likely the victims were Neolithic migrants, "members of the communities that established farming and animal husbandry on the Iberian Peninsula," the researchers say.

Their attackers could have been another roving band of migrants or indigenous hunter-gatherers. If they were the former, a territorial dispute could explain the violence. If they were the latter, then they might have viewed the migrants in El Trocs Cave as invaders encroaching upon their foraging grounds.

Whoever carried out the massacre and for what reasons, the remoteness of the scene and the motive for violence seemed to have resulted in a "killing frenzy," according to the researchers.

"Els Trocs probably documents an early escalation of inter-group violence between people of conceivably different origins and worldviews, between natives and migrants or between economic or social rivals. The conflict conveys the impression of a xenophobic action; the type of aggression suggests a clash between enemy groups."

Source: Alt, K.W., Tejedor Rodríguez, C., Nicklisch, N. et al. "A massacre of early Neolithic farmers in the high Pyrenees at Els Trocs, Spain." Sci Rep 10, 2131 (2020). https://doi.org/10.1038/s41598-020-58483-9