OK, I'm going in... I did this before, didn't accomplish much, but hope springs eternal. Before I begin, let me detail my experience (again) in this area. I'm a retired LAPD Detective supervisor, with 24 years on the streets of Los Angeles. I investigated or helped investigate dozens of shootings, and was involved in probably a hundred other shooting calls, including Officer involved. I was personally involved in more than one shooting, and understand what the shooter experiences. And when the inevitable accusation comes from someone here (like before) that I may not be who I say I am, I don't really care. But there are several here on this forum (including Massad Ayoob) who do know me professionally; if you wish, I'll go down that road later.
1. Clamming up after a shooting is stupid. It didn't help Jesus during his investigation, and it won't help you. You, as a gun-carrying citizen, have a responsibility to report certain things to the responding officers. If you're not prepared to do that, you shouldn't be carrying a weapon.
2. Just like a car-wreck, you need to tell the responding cops what happened. "Signing a complaint" happens in spousal boxing capers, not shootings. You're NOT going to be interviewed at the scene, anyway. You'll be transported to the station almost immediately, "on ice", to await the investigating detective(s), who will go to the scene first, and will most probably know exactly what happened when you're interviewed (notice I didn't say "interrogated") at the station. At the scene, after the responding patrol cops have contained the crime scene, you should be prepared to give a safety statement; this is a response to "how many were there?" "Which way did they go?" "Are any wounded?" "What were they wearing?", "How many shots did you fire and which direction", etc. If you're not sure, say so. If you don't know, tell the officer. You MUST do this. Refusing to do so handicaps the officers trying to capture outstanding suspects and setting up a perimeter. If your case DOES go to court (including civil), refusing to help responding officers in capturing outstanding suspects won't look too good. Remember your responsibility as a citizen.
3. After the detectives have conducted a walk-through and completed the preliminary investigation, they will talk to you at the station. This may well be several hours later. In the meantime, you'll probably be sitting in the detective's office, with a patrol cop baby-sitting you. Do not talk to him about what happened. He doesn't really care and doesn't want to be there, but he will tell the detectives what you said. So yes, this is a good time to shut up. You won't be in handcuffs, unless this was a clear-cut murder; different advice then applies. We're talking about an obvious self-defense shooting, not killing a 13-year-old for egging your house.
4. Detectives will return and interview you. If this is a poor shooting (not self-defense), you'll be given a Miranda warning (it's a warning, not a right). Ask for a lawyer and if you choose, refuse to speak. You'll be booked for whatever you did, and it'll go to court, or a plea, whatever. We're not talking about that here, though. If you shot someone in your home at 4 am after they came through a window, TELL THEM. It's obvious to the dicks what happened. If you're not sure of the time, how many shots were fired, where the wife was, etc, say that. Be clear, concise and answer with yes and no responses. The detectives will ask you what they want to know. They're not interested in railroading you; they only want to solve the crime and go home. Your "statement" will be brief. "I was awakened by breaking glass. I got up, retrieved my pistol and went into the living room. I saw someone there. He approached me; he wasn't a member of my family, he wanted money. He said he'd kill me. I shot him. I don't know how many times. He fell down there. I told my wife to call 9-11. Two patrol units responded a few minutes later." That's it. Most of the time, I transcribed what the shooter said, repeated it back, made corrections, had him sign it, and that was it. It was purposely made VERY vague for future facts to be added as the investigation continued. I wasn't interested in screwing over someone that did exactly what I would have done. The crime scene would be walked over several more times, reports reviewed up to captain (or higher) level, discrepancies noted and explained (every cop knows there will be conflicting statements; if there wasn't, I'd be concerned and suspicious), and crime scene data analyzed. You, the shooter, will be talked to several more times. All this happens BEFORE the DA (District Attorney) sees the case. When it's presented to the DA, the investigating detective gives recommendations. It's unusual for the DA not to concur. I was involved in many of these, and no lawyers were needed. This includes several attempted robberies of citizens, store owners and people inside their residences. All were good shootings and came back as justifiable. You want to play dumb, say nothing, hamper an investigation that's obviously a SD shoot, go ahead, but you're needlessly pissing off the investigator and not helping yourself. Your call.
5. If you shot the kid next door while he was climbing out of your daughter's room, shot a transient asking for change at the 7-11 or killed the ex-wife's new boyfriend, my advice doesn't apply. Keep your mouth shut, ask for your attorney and hope for the best. Some of the things said here border on the bizarre and are quite silly. You don't need to say "I was in fear of my life". That's obvious and sounds dumb. Asking for an RA unit (Rescue Ambulance) for yourself because you feel weak or sick is also silly; there'll be one or two around anyway. And if you you're so out of control after shooting someone that you can't think, must "throw up" or can't calm down enough to answer a couple of simple questions ("which direction did the car go?"), then you shouldn't be carrying a gun. CCW is something that isn't for everyone, despite what some may think. You must be calm, deliberate, decide when and when not to shoot, pick your shot, then prepare yourself for the inevitable troubling aftermath. If you can't, then don't carry. My view, based on 24 years of police work in the City of Angels.
Bob