New research suggests dozens of Bronze Age Britons were killed in an attack unlike any previously known to archaeologists studying the time period and location.

The study of human remains from Charterhouse Warren in south-west England, carried out by a team of researchers from several institutions including the University of Oxford, was published in Anticajournal of world archaeology. At least 37 Bronze Age men, women and children were found to have been “killed and butchered” and then cannibalised, their bodies then dumped into a natural shaft almost 50ft deep. Although archaeologists have found remains of Bronze Age Britons who later died violently, these incidents were largely isolated. Mass graves from that era have also been found, but the remains were laid to rest with respect, unlike those studied.

Researchers first became aware of the shaft in the 1970s. In the 1970s and 1980s, two excavations were carried out. Human remains, as well as some artifacts, including a flint dagger, were found in several places in the shaft during these excavations. In total, more than 3,000 individual human bones and bone fragments were found. These bones were used to estimate that the shaft contained at least 37 individual sets of remains. The different lengths of the bones indicate that the people killed were both men and women, and that they ranged in age from infants to adults. Ongoing research is working to determine how these people were related to each other.

The way the remains were disposed of allowed for a detailed examination, the researchers said. The handle helped preserve the bones and keep them grouped together.

The bones “show clear evidence of blunt force trauma,” according to the researchers, suggesting that many of the people in the shaft “suffered a violent death.” Other injuries likely occurred, including the removal of the scalp and severed muscles in the jaw suggesting the removal of the tongue or lower jaw, as evidenced by bone marks, the researchers said. Some of the victims may have been decapitated or dismembered.

It’s possible the victims were captured or ambushed because of the severity of their injuries, researchers said. It is not clear who may have carried out the attacks.

There is also evidence that the bodies were cannibalized, the researchers said, including traces of human teeth on the bones and indications that bone marrow, the soft tissue inside the bones, had been removed. The researchers said the cannibalism was likely carried out “in the context of violent conflict, in which individuals were dehumanized and treated like animals.”

“Approximately 37 men, women and children – and possibly many more – were killed at point blank range with blunt objects, then systematically dismembered and stripped of their flesh, and their long bones broken in a manner that can only be described as slaughter.” the researchers said.

Later in the publication, the researchers called the scene a “massacre” and suggested it may even have been a “political statement” of violence so brazen it would “resonate across the wider region and over time”. However, it is not clear what could have led to the violence: “Neither climate change, ethnic conflict, nor competition over material resources appear to offer plausible explanations,” according to the researchers, leaving the only plausible option is that the violence erupted as part of a pattern of revenge or violence between community.

“At this stage, our investigation has raised as many questions as it has answered,” the researchers said. “Work is underway to shed light on this extremely dark episode of British prehistory.”