Nearly half a million years ago, an ancient human was murdered. With two brutal blows to the head, the attacker fractured his victim’s skull, killing him (or her). The lifeless body was then brought to a communal burial site and dropped down a 43-foot shaft into a mass grave known as the “Pit of Bones.” The remains lay there for millennia, the fact of their owner’s life and violent death lost to time.

Until now.

In a study published Wednesday in the journal PLOS One, scientists have reconstructed that ancient death scene based on fragments of the victim’s fractured skull, which were found alongside the remains of 27 other individuals in northern Spain’s “Pit of Bones.” Little is known about the skull’s owner — gender, background, lifestyle — but one thing seems for sure: This human’s damaged skull is evidence of the world’s oldest known murder.

Scientists can tell this because of the nature of the injuries. After reconstructing the prehistoric skull, dubbed “Cranium 17,” from about 50 fragments found in the pit, they identified two prominent holes in its forehead, just above the left eye. While it’s possible that the injuries came from a hunting accident or a fall, researchers say that a deadly, frontal attack by another human is the best possible explanation. The fractures show no signs of healing, indicating that the skull’s owner died before recovering from the injuries. And the shape, size and location of the holes suggest that they were produced by a single instrument in a face-to-face fight, rather than an accidental blow; accidents tend to happen to the side of the head, the authors point out, while attacks come from the front. What’s more, the fact that there are two direct blows makes it unlikely that this killing was anything but intentional — you don’t “accidentally” crack a hole in someone’s skull two times in a row.

The technical term for this is “blunt force trauma,” and researchers say that the skull is the earliest evidence yet of deadly “interpersonal violence” between humans.

“Murder is an ancient feature of humanity,” co-author Rolf Quam of Binghamton University told NPR.

It’s a sobering thought. But, lead author Nohemi Sala pointed out, we don’t know if the skull’s prehistoric owner had it coming.

“Unfortunately, the intentions do not fossilize, so it is impossible to interpret the motivation of the killing,” Sala, a paleontologist at Spain’s Complutense University of Madrid, told Reuters. “Not even Sherlock Holmes could help us in that.”

The prehistoric people found in the bone pit weren’t modern humans. They were members of Homo heidelbergensis, an ancestral human species that wandered Europe, Africa and possibly Asia during the Middle Pleistocene (roughly 700,000 to 200,000 years ago). According to the Smithsonian Museum of Natural History, these humans were pioneers in areas other than the killing of their peers: They were the first to live in colder climates, the first to routinely hunt large animals and the first to build shelters.

The discovery of the “Pit of Bones” suggests another unique feature of these early humans: They cared for their dead. The authors of the PLOS One study believe that the 28 skeletons found in the pit could only have been placed there intentionally.

“Other humans went to the top of this vertical shaft and deposited dead members of their social group down into the site, and in this way formed a kind of primitive cemetery or kind of an early manifestation of funerary practices,” Quam told NPR. “Clearly this is an intentional human disposal of the dead.”

If Quam and his colleagues are right, the pit is the oldest evidence of ritual burial known to science. It means that humans there may have been the earliest modern mourners as well as the earliest murderers.