Did Moses Sin? [100WW]

Did Moses sin when he slew the man, adopted kinsman giving great grief to Moses' true blood? He acted in haste, in youthful and justifiable rage. Did he mean to kill? If murder, in what degree? All parties felt the deed's wrongness: his own kinsman the next day, Pharaoh who came after him for it, Moses himself who fled. The law expresses the eternal character of God: therefore, murder is always wrong. Vigilante justice may be right sometimes, but it's not legal. Does Moses' sense of guilt mean he sinned? Perhaps not. I think he sinned. What do you think?