Although I've been accused here of not having a L/E career, I DID, and I can tell you Williamlayton is correct. Nothing you can say to police will be of benefit at trial, unless it's a spontaneous remark about fear. If you were not afraid for your life (or someone else's), you probably shouldn't have fired. Other than that, most everything you say is evidence not in your favor. SHUT UP! No harm can come to you from not talking, even if you are totally in the right. Police arrive on any scene to: firstly, protect life, and secondly, enforce the law. They WILL do both. That said, if and when you have to shoot someone, you can't waste seconds thinking about trial. That'll get you dead. But in the back of your brain, remember that when someone is hurt or dies from the direct result of your action, the police will be interested. They don't come to your house or to the scene to make friends. They come to do their job.
That said, I don't remember or know of a single case wherein a person legally defending their life, suffered a conviction, UNLESS, they somehow promoted the altercation. Example: If you instigate an argument and it ends in a shootout, you're defense is weakened. Some few states say you don't have to run away from an altercation; that you can stand your ground. Most states say if you could have prevented killing by running away, you must. Each case, of course, will be adjudicated on its own merits. Let's say a hoodlum greets you on a darkened street with a big knife and tells you to get off HIS street. You could easily enforce your right to be there. But, if you shoot him because he brandishes a knife, and you have sufficient distance between you and him that you could run, what would you do? More importantly, what will the court say you should have done? I like scenarios. They were presented to me without end during basic and in-service training. Some were on the range, where particular circumstances were shown on screen, and I had to make an instant decision re. deadly force. The point is , if you ain't a cop, don't shoot unless there's no alternative. Police have to stand their ground, and stay on dangerous ground until the matter is resolverd. We don't usually have that luxury. Don't shoot because you CAN, shoot because you must.