When I was playing last night I made it to Riverwood and noticed a random dead guy laying in the middle of the road.

After making sure I hadn't blacked out and murdered someone again, I looted his corpse and moved on; as one is supposed to do when you are the savior of the human race.

That said, I think this guy was just dead randomly. I read later he was integral in some quest present in Riverwood, and thus I question his premature exodus from the game as a glitch and not the act of roving giants.