A collection of prehistoric human remains has revealed horrifying glimpses of a brutal massacre that took place more than 4,000 years ago.

For a study published in a journal Antiquityresearchers analyzed more than 3,000 bones and bone fragments attributed to dozens of individuals from the Early Bronze Age site at Charterhouse Warren in southwest England.

A little-known collection of skeletal remains – which is “unique” in Britain – has revealed that the individuals were killed, dismembered and probably partially consumed before the remains were dumped down a nearly 50ft deep natural shaft. The authors of the study believe that all of this happened during a single event that occurred sometime between 2210 BC and 2010 BC

The level and scale of violence that occurred during this event is “unprecedented” in British prehistory as far as we know, the authors said.

Direct physical evidence of violence in Early Bronze Age Britain (approximately 2,500 BC to 1,500 BC) is generally very limited, despite the fact that hundreds of skeletons have been found from this period.

He added: “We actually have more evidence of conflict from the Early Neolithic (about 1,500 years before Charterhouse) and the Middle and Late Bronze Age, when the first tailored weapons – swords – appeared, along with hillforts in the late but sometimes a single side can to radically change our perception and I think Charterhouse has the potential to do that.”

“Charterhouse Warren is one of those rare archaeological sites that challenges the way we think about the past,” Schulting said in a news release. “It’s a stark reminder that people in prehistoric times could cope with more recent atrocities and shines a light on the dark side of human behaviour.”

The Charterhouse Warren bone assemblage was discovered by chance in the 1970s by a group of cavers searching for a new cave system in the area. Before the latest study, however, very little was known about the bones.

In an effort to clarify what happened to these individuals, the research team analyzed the remains, identifying numerous cut marks, perimortal fractures (ie created around the time of death) and blunt force trauma to the skull. The team’s findings suggest that the victims were killed at close range with blunt instruments before being systematically cut up, butchered and possibly partially consumed.

“The main thing we’ve shown is the size of the gathering and the scale of the evidence for the violence,” Schulting said. “We identified many blunt head injuries, indicating that all individuals had been killed. And although cut marks had been previously noted, there was no indication of a systematic way in which the victims were cut open, flesh removed and bones shattered.”

The researchers were also able to show that at least 37 individuals, including men, women and children, are represented in the bones, indicating a community.

“It is likely that there were even more, as we can only calculate a minimum number,” added Schulting.

Since there were no signs of a struggle, it is likely that the victims were taken by surprise when attacked by enemies.

Numerous beef bones are mixed with the human remains at the site, suggesting that the attackers did not need to eat their victims due to lack of food. Instead, the authors suggest that cannibalism may have served to dehumanize them.

The researchers then explored the question of what might have motivated such acts of extreme violence. Climate change and resource competition do not appear to have been factors that exacerbated conflict in Early Bronze Age Britain. There is also no evidence of inter-ethnic conflict. This suggests that social factors may have been the main factors. During this period, potential triggers for violence could include theft, perceived insults and insults, and accusations of witchcraft.

The extreme violence that once took place at the site is probably not an isolated incident, according to Schulting. Such an event would likely have repercussions as relatives and friends of the victims sought revenge.

“Although not typically detectable in the archaeological record, cycles of tit-for-tat revenge can escalate dramatically and may be completely out of proportion to the original act,” the authors wrote in the study.

“At this stage our investigation has raised as many questions as it has answered. Work continues to shed more light on this decidedly dark episode of British prehistory,” Schulting said.