Scientists have discovered what may prove to be the oldest example of intentional violence among humans. In fact, the individual who died of apparent head wounds over 430,000 years ago is not exactly "human," but one of our close cousins, a Neanderthal. And what his skull may prove is that violence predates the rise of modern humans.

The skull was among 28 individuals whose skeletons were discovered deep within a cave system in Northern Spain. The pit, known as Sima de los Huesos (Pit of the Bones), appears to have been a place where the bodies of Neanderthals were deposited, and their bones have provided a glimpse at life, and death, among some of our ancient ancestors.

The skull was found in about 50 fragments. And it wasn't until it was reconstructed that researchers realized the skull showed signs of serious injury.

"This individual was killed in an act of lethal interpersonal violence, providing a window into an often-invisible aspect of the social life of our human ancestors," says paleontologist Nohemi Sala of Madrid's Centro Mixto UCM-ISCIII de Evolución y Comportamiento Humano.

The skull in questions shows two injuries above the left eye - injuries that occurred right around the time of death, based on evidence obtained through CT and microscopic analyses. The penetrating wounds are identical in size and appear to be from the same instrument, which indicates the blows were delivered intentionally. It is unknown whether the individual was male or female.

"Based on the similarities in shape and size of both the wounds, we believe they are the result of repeated blows with the same object and inflicted by another individual, perhaps in a face-to-face encounter," Sala says.

Bioarchaeologists use forensic techniques to analyze traumatic injury on ancient skeletons. Often, the nature of the wounds says something about their context. And it's the context of such events that help reconstruct social structure among prehistoric populations.

"Since either of these wounds would likely have been lethal, penetrating the brain, the presence of multiple wounds implies an intention to kill."

And if the scientists are correct in their assessment, the skull represents the earliest clear case of deliberate interpersonal violence among our fossil ancestors. Their research was just published online in PLOS One.