Fantastic Four, Vol. 1

The Crusader keeps attacking bank after bank. They eventually deduce that he is Robert Grayson, which Crusader himself believes, although it will be revealed much later that he is actually Thelius, a Uranian with a physical resemblance to Grayson who has been imprinted with Grayson's memories. Nonetheless, the team deduce that Crusader is solar powered, and manage to cut off his power supply so that they can face him and stop his spree of violent attacks.