A person may only use lethal force as a last option. The individual must have a reasonable belief that he or she or another person is in immediate risk of serious bodily injury and that there are no other reasonable measures of protection or escape. Force may be used to prevent death or great bodily harm to yourself or another person. The first thing you need to know if you're shooting someone in self-defense is whether they were actually trying to hurt you. If you find out that they were, you have the right to defend yourself. However, if they weren't trying to do you any harm, then you should call the police instead. They can take care of investigating whether they needed to use deadly force. It is important to understand that using deadly force is not justified simply because you feel like it might be necessary. There must be an actual reason for believing that you or another person's life is in danger. The best example of when lethal force is acceptable is in cases where you are defending yourself from someone who is trying to kill you. For instance, if a person attacks you with a knife or a gun and you fear for your life, then you have the right to use deadly force to protect yourself. However, if a person isn't doing you any harm and you just feel like killing them, this would not be acceptable behavior.