Lethal wounds on an ancient human skull may point to one of the oldest cases of murder on record, a new study reports.

The skull, 430,000 years old, was found deep in an underground cave system at Sima de los Huesos, an archaeological site in northern Spain. The small chamber is accessible only through a vertical shaft 43 feet deep.

Composed of about 50 fragments, the nearly complete skull is described in the current issue of the journal PLOS One.

The skull has two penetrating lesions above the left eye. They are nearly identical in size and shape — and, researchers concluded, likely caused by repeated blows made by a single instrument.