First of all, let's get something out in the open...
If it's a good shoot, it's probably not going to be prosecuted. That is, if the corpse was attacking you, had broken into your occupied home, exhibited any kind of weapon to obtain valuables or committed any kind of felony crime against you, it's unlikely a DA will waist his time trying to prosecute you. That's assuming there are witnesses or evidence to support the contention of self-defense. It may get a little muddy if you're in the woods or at a deserted rest stop, however.
In certain jurisdictions, however, it may be that any case where there is the slightest doubt, the prosecutor will push hard for an indictment. Some D.A.'s have the strange notion that any citizen killing another person, even in self-defense, must be involved in some kind of criminal activity or be a morally corrupt person. It's in these cases we usually see the truth distorted for political gain.
If you're dragged into court in one of these situations, it's always good to spend time talking to your lawyer about any "technical" issues -- such as the use of certain ammo, the type of gear you carried, why O.C. spray wasn't used, why fleeing wasn't an option, etc. Usually the defense gets to know that the prosecution will try to prove with the evidence which allows time to build rebuttals to dramatically misleading statements about the performance of guns, bullets or O.C. sprays. It's also a good time to review any kind of public statements you've made (here or elsewhere) that could be shown in a negative light.
If prosecutors proclaim the bullets are "devastating" for their "explosive effects" your lawyer should be objecting over "facts not in evidence" and challenge the D.A. to show that your ammo does so. Further, your attorney should be reminded to rebut those points when cross-examining witnesses, especially professionals. It may be that simply asking a police officer if he knows that 'x' agencies in the state issue hollow-point ammo.
Much harder is when the prosecution attacks your personal character and credibility. Being caught in a lie to the Police is often damning, but not insurmountable. Having them catch you in several lies destroys your credibility. It's best to say as little as possible until your attorney is present. Things you DO say should be things that will help you later -- such as
- pointing out where a weapon was dropped if it isn't plainly visible
- that one of the grocery-store's bag boys might have witnessed it before running inside.
- The description & direction of travel of an accomplice
- Any assault or injury you sustained (from hands grabbing you to broken bones)
Having such statements at the scene show some cooperation for the investigation and document essential facts without going into detail. Once stated, it's time to avoid trying to be detailed and wait for your lawyer.
I think most cops can probably judge if it's a reasonable shooting or not pretty quickly. I also think that most cops, when they find a legitimate SD shooting, tend to be sympathetic with the defender. That doesn't mean you should be chatty with them, however. But they may not be your enemy either.