It turns out that this may have been the grave for an elite Viking killing force of mercenaries:
It was a deliberate execution and decapitation only of men of fighting age, and most interestingly for Dr. Baillie, these men weren’t decapitated by a blade to the back of the neck. They were decapitated from the front, just like the captured warriors in the Saga of the Jomsvikings, an Icelandic saga about a quasi-legendary fighting force of Viking mercenaries who were reputedly the fiercest of all Viking warriors.
Read the rest. Fascinating and grim stuff.