The decapitated heads of young women from a prehistoric Andean village were put on display before they were discarded in a rubbish dump — possibly in an effort to terrorize people living under Incan rule.

Francisco Garrido and Catalina Morales at the National Museum of Natural History in Santiago examined four skulls found at the ancient settlement of Iglesia Colorada, located in modern northern Chile. The researchers determined that three of the skulls belonged to girls or young women; the fourth skull belonged to a child of undetermined sex. Holes were punched into the skulls, probably so they could be strung on ropes. The skulls were eventually consigned to a rubbish pile amid food scraps and other debris.

This treatment was carried out at roughly the same time that the Inca conquered Iglesia Colorada in the fifteenth or sixteenth century AD. The trophy heads might have been an imperial tactic for repressing local discontent, the authors say.