That depends entirely on the local law. It's impossible to answer this question without knowing your location as laws governing this issue vary widely. You can use the Find Law site to discover what the law is in your area if you don't want to disclose your location here.

I would say its self defense for a breaking and entering, plus...if he is threatening then he could possibly have intended to hurt her. Plus its her property. Hes totally the crimal and she did it in self defense.

In most US States you are within you right to defend yourself upto and including the use of deadly force in your own home.You may not use force to defend your property,but you can to defend your life and that of third parties ie your family.All this said it does not mean that some DA will not charge you with a crime including murder or manslaughter. Sometimes the fight for your life starts after the bad guy is dead.

In most jurisdictions, you are entitled to defend yourself and others by whatever means are necessary, which may include lethal force. Where people tend to misunderstand is that you are only entitled to use lethal force *while you or others are being threatened*. If the intruder has stopped being threatening - e.g. you have already winged them, or they are running away, or have dropped their weapon and raised their hands, you are no longer entitled to use force against them. Prosecutions have usually been against people who have not stopped hurting the intruder when the intruder is no longer a threat, or who have taken it upon themselves to punish a now-unthreatening attacker. Because it was very much right to defend yourself when attacked, this does not justify continuen the "defence" when the attack has stopped.

"Bust into my house and see what happens" thats what my buddy next door says."you wan't convict me will you judge?" Well you can't just shoot folks John! Inside I say hell no,You get a pass but be right.

Follow up. Sometimes the fight for your life starts after the bad guy is dead.Thank god some of us go before Judges like me!

It depends on the laws of your particular state, but generally, when you are defending yourself, you're only allowed to use the minimum amount of force necessary to repel the attack, and the injury inflicted on the aggressor must be somewhat proportional to the injury that you anticipate being inflicted upon you. So, if somebody is about to punch you in the face, you can't kill them in self-defense, but you could use some lesser degree of force. On the other hand, if someone is about to kill you, or inflict a serious bodily injury against you, you can usually use deadly force. Many states require you to attempt to retreat before resorting to force, and only allow you to use force in self-defense if you have already attempted to retreat, or it is impossible to safely do so. However, most states that have this rule also have an exception, known as the "castle doctrine" - based on the premise that a person's home is their "castle" - nobody should be expected to flee from their own home. In such a case, you can use force to defend yourself without having to flee first. Remember, though, that deadly force is never justified to defend property. Even in the event of a home invasion, you can only use deadly force if you reasonably believe that the burglar is going to cause you death or serious bodily harm. However, by breaking into an occupied home, such intent can usually be presumed. http://www.legalmatch.com/law-library/article/self-defense-lawyers.html