Talk about a cold case: Archaeologists are investigating a 5,000-year-old mass murder that confirms the brutality of late Neolithic life, LiveScience reports. Eight years ago, a grave was discovered in Poland with 15 women, young men, and children, all killed by head wounds and buried alongside funerary gifts like ceramic jugs and flint tools. But why were massacred victims buried so nicely? New analysis of the skeletons' DNA suggests it was all about family. "We can see that mothers are laid next to their children and brothers side-by-side," says study author Morten Allentoft, per CNN. "Those who buried the dead knew them well." But aside from one man lying between his wife and son, there are no adult males. And that may explain the killing.
"Our suggestion is that [the men] weren't at the settlement when the massacre occurred and that they returned later, and subsequently buried their families in a respectful way," says Allentoft. Whether the men fled or weren't home is unclear, but it seems the victims were executed, a common tragedy at a time when resources were running thin and populations were expanding. Two other takeaways: The burial reveals the importance of family in the so-called Globular Amorpha culture, which had only been hypothesized until now, per Fox News. And the killers remain unknown, though another researcher says Yamnaya cultures migrating from the east were transforming European cultures: "It is easy to imagine that these changes somehow precipitated violent territorial clashes," he says. (Read more mass graves stories.)