At least two people were killed and three seriously injured in a nightclub shooting in the German city of Constance. Police said, a man opened fire early morning today, killing one person. The gunman was then shot dead in an exchange of fire with police.<br/><br/>Witnesses said, a doorman appeared to have been shot as he tried to stop the attacker. A police spokesman said, Guests were able to save themselves by fleeing outside or hiding.