Scientists say they have uncovered the remains of the earliest known massacre victims, dating from approximately 10,000 years ago.

Archaeologists believe the victims were members of an extended family group of hunter-gatherers who were slaughtered by a rival group.

According to the scientists' report in the journal Nature, parts of 27 skeletons were discovered near Lake Turkana in northern Kenya. Ten of the twelve relatively complete skeletons showed signs of a violent death, including smashed skulls and faces, broken ribs and evidence of arrow wounds. 

Partial remains of 15 other skeletons were also found and are believed to belong to victims of the same attack. The group included the skeletons of at least eight women and six children. A fetal skeleton was also found in the abdomen of one of the female skeletons.

"The ... massacre may have resulted from an attempt to seize resources – territory, women, children, food stored in pots – whose value was similar to those of later food-producing agricultural societies, among whom violent attacks on settlements became part of life," said lead study author Dr. Marta Mirazón Lahr of the University of Cambridge.

The find offers compelling evidence in the scientific debate about whether human aggression was passed on to us from our primate ancestors or emerged after the development of agriculture and settled, hierarchical human societies. The earliest known so-called "war grave" before the latest discovery was found in Germany and dated to approximately 5000 B.C.

"I’ve no doubt it is in our biology to be aggressive and lethal, just as it is to be deeply caring and loving,” study author Robert Foley of the University of Cambridge told the Daily Telegraph. "A lot of what we understand about human evolutionary biology suggests these are two sides of the same coin."