Good one Len. I would find it hard to place the baserunner back at 1st base since he was already going on he pitch, before it hit the batter. But if I were to hazard a guess as to what the actual rule states, I would say the runner must go back to 1st. But I won't be surprised which ever way this one goes.
**Edit: Dead ball - One from the mound, two from the field?
**Edit: Dead ball - One from the mound, two from the field?