By FRANK JORDANS, Associated Press

BERLIN (AP) — Scientists say they have found rare evidence of a prehistoric massacre in Europe after discovering a 7,000-year-old mass grave with skeletal remains from some of the continent's first farmers bearing terrible wounds.

Archaeologists who painstakingly examined the bones of some 26 men, women and children buried in the Stone Age grave site at Schoeneck-Kilianstaedten, near Frankfurt, say they found blunt force marks to the head, arrow wounds and deliberate efforts to smash at least half of the victims' shins — either to stop them from running away or as a grim message to survivors.

"It was either torture or mutilation. We can't say for sure whether the victims were still alive," said Christian Meyer, one of the authors of the study published Monday in the journal Proceedings of the National Academy of Sciences.

Meyer said the findings from Schoeneck-Kilianstaedten bolster theories put forward after the earlier discovery of two other grave sites in Germany and Austria. At all three sites, the victims and the perpetrators appeared to have been from the Linearbandkeramik — or LBK — culture, a farming people who arrived in central Europe about 5,500 B.C. Their name derives from the German phrase for "linear band ceramics," a reference to the style of their pottery.

Intriguingly, the sites have all been dated toward the end of the LBK's 600-year presence, suggesting that members of this culture — which is thought to have developed in what is now Hungary and spread along the Danube River — may have turned on each other.

"It's about finding patterns. One mass grave was spectacular, but it was just a single grave. But when several such sites are found from the same period, then a pattern emerges," said Meyer.

In their article, the authors suggested that "the new evidence ... in conjunction with previous results, indicates that massacres of entire communities were not isolated occurrences but rather were frequent features of the last phases of the LBK."

Chris Scarre, an archaeologist at the University of Durham, England, who wasn't involved in the study, said its conclusions seemed well supported by the evidence.

"What is particularly interesting is the level of violence. Not just the suppression of a rival community — if that is what it was — but the egregious and systematic breaking of the lower legs," said Scarre. "It suggests the use of terror tactics as part of this inter-community violence."

Meyer, an anthropologist at the University of Mainz, Germany, said nobody can say for sure what prompted the killings so long after the fact. But it's possible to put forward theories, based on what's known about the LBK culture and the conditions they faced. For example, the end of LBK culture coincided with a period of climate change.

"The LBK population had expanded considerably, and this increases the potential for conflict," said Meyer. "Also, the LBK were farmers, they settled. So unlike hunter gatherers, who could move away to avoid conflict, these people couldn't just escape. Add to this the fact that there may have been a period of drought that constrained resources, causing conflicts to erupt."

Meyer said the theory of conflict between different groups within the LBK is supported by the existence of an apparent ancient border near the Schoeneck-Kilianstaedten site. Archaeologists have found that flint was traded on either side of the divide but not necessarily across it — suggesting the two groups did not see each other as kin, he said.

The attackers, however, spared some members of the group, with victims skewed toward young children, adult men and older women.

"It's likely that the young women, who are missing in the grave, were kidnapped by the attackers," said Meyer.