I always like a good medieval skeleton story, don't you? These fellows were discovered at St. John's College in Oxford in 2008. Originally, they were thought to be a part of the St. Brice's Day Massacre. You remember that one, don't you? From 13 November 1002. No? Don't feel bad, neither do I. King Æthelred the Unready, tired of all these bloody Vikings and of those who stayed and settled, ordered all the Danish men in England to be put to the sword. Not a nice thing but pretty medieval. He believed that they would take orders from their Viking overlords and kill the king and all his counselors.
In fact, here's Æthelred's royal charter from 1004 explains why he did what he did:
"For it is fully agreed that to all dwelling in this country it will be well known that, since a decree was sent out by me with the counsel of my leading men and magnates, to the effect that all the Danes who had sprung up in this island, sprouting like cockle amongst the wheat, were to be destroyed by a most just extermination, and thus this decree was to be put into effect even as far as death, those Danes who dwelt in the afore-mentioned town, striving to escape death, entered this sanctuary of Christ, having broken by force the doors and bolts, and resolved to make refuge and defence for themselves therein against the people of the town and the suburbs; but when all the people in pursuit strove, forced by necessity, to drive them out, and could not, they set fire to the planks and burnt, as it seems, this church with its ornaments and its books. Afterwards, with God's aid, it was renewed by me."
In fact, they didn't just put men to the sword but women and children, too. But in analyzing these particular bones, scientists came to the conclusion that the "bone collagen suggests a diet more like other Scandinavian populations than that of local groups, and the (tooth) enamel isotopes point towards a Scandinavian rather than a lowland English origin. Comparison with Oxford Archaeology's recently excavated Weymouth Ridgeway mass burial suggests, however, that the execution of a captured raiding party is more likely than the slaughter of Oxford inhabitants of Danish descent."
So...not local Danish? Best summation from the facts that they were a raiding party, between the ages of 16-25, with multiple stab wounds. More can be found here from the folks at Medievalists.net.