The remains of at least 27 individuals in Kenya show evidence of violent murders that took place around 10,000 years ago, and may be the earliest instance of warfare on record.
Nature Journal published the findings on Wednesday about the grisly discovery; many of the deceased had fractures, and some had been tied up before they were killed. None of the dead were buried. The authors say this is the earliest extant evidence of a group of humans killing another group intentionally.
"These human remains record the intentional killing of a small band of foragers with no deliberate burial, and provide unique evidence that warfare was part of the repertoire of inter-group relations among some prehistoric hunter-gatherers," said lead author Marta Mirazon Lahr in a statement.
The remains exhibited evidence of blunt force trauma such as crushed skulls and wounds from spears or projectiles. Two sharp obsidian weapons that weren't native to the area were found amongst the skeletons, leading the researchers to conjecture that the murderers travelled from elsewhere.