About 10,000 years ago, a group of attackers massacred a band of Stone Age hunter gatherers tying them up like captive animals, killing them with clubs, arrows and stone blades and dumping their brutally murdered remains into shallow waters.
The skeletons of these 27 people, which were found at Nataruk west of Lake Turkana in Kenya, now offer the oldest evidence of human warfare.
The discovery, which was published in the journal Nature on Wednesday, offers graphic details of how this group of people including at least eight women and six children were massacred to their death.
A woman in the last stage of her pregnancy was bound by her hands and feet. One man sustained wounds and a crushed skull which appear to have been inflicted by blows of a club. Another man's skeleton had a sharp blade made of volcanic glass known as obsidian still implanted in his skull.
"The remains from Nataruk are unique, preserved by the particular conditions of the lagoon with no evidence of deliberate burial," the researchers wrote in their study.
"They offer a rare glimpse into the life and death of past foraging people, and evidence that warfare was part of the repertoire of inter-group relations among prehistoric hunter-gatherers."
Study researchers Mirazón Lahr, paleoanthropologist from the University of Cambridge, said that evidence suggests the massacre was a premeditated attack by a troop of raiders, who possibly hailed from another region. The victims, on the other hand, may have been members of an extended family.
The researchers added that the extreme violence appear to be a typical occurrence. The mass murder, according to Lahr, was a standard antagonistic response when two social groups encounter during that time.
The Nataruk massacre could be the result of an attempt to seize resources such as food stored in pots, territory, women and children. The researchers likewise said that the brutality of the murder was not a remote incidence. Attacks appear to be common among nomadic hunter gatherers.
"The deaths at Nataruk are testimony to the antiquity of inter-group violence and war," said Lahr.
"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."