Memes

That would explain that part that says

PS: "Oh yeah that Agent Smith guy who called in this arrest, he needs to be promoted and his co-workers need to stop complaining about his body odor, because it's quite pleasant actually. Prefer it to an air freshener."

In which timeline are you? Harambe alive or Harambe dead?

the second actor, having commited no crimes, proves his innocence.

Here's the flaw in your plan: This doesn't actually work in the US.

if luigi hypothetically did participate in this plan, wouldn’t that itself be a crime (accessory to murder)? so they could still get him for something if they found out about the plan, but probably for less than if he did actually kill someone. i’m not a lawyer though so i don’t really know how this stuff works or if it would even be feasible to prosecute him for any of those things (if he did them)

Why not? The double jeopardy clause is about prosecuting a single person twice; it says nothing about prosecuting a second person for the same crime. Heck, convicting a second person wouldn't even automatically invalidate the first conviction. (SCOTUS has ruled that innocence is not a sufficient reason to overturn a conviction.)

Remember, we have a judicial system. Calling it a "justice system" is inaccurate.

Except DB Cooper was just a crook who was only after money. The shooter had an actual statement to make.

I think he wanted to be caught and make a statement. "Those parasites had it coming"

The thing is, whoever did it was pretty smart about much of the crime, which is why the story of how Luigi was caught and what they say he had on is person seems so odd relative to the behavior the previous week.

If it was Luigi, he was pretty disciplined and smart before, during and immediately after the crime with the only leak being showing his face at the hostel (which he may have been required to do when he gave them ID).

If he did do it and really had all that evidence on him, maybe he wanted to get caught? It seems crazy that anyone would hang onto a 3d printed gun when it would be pretty easy to destroy and dispose of it in multiple pieces and locations.

I’ve said it before but I truly believe that Luigi would still be free if he had plucked his eyebrows, regardless of whether he did it.

Edit to add, maybe he thought he’d get shot or captured at the scene and didn’t think too far beyond the immediate getaway? And with the stress of his picture up all over the news and social media, he kinda wasn’t thinking straight?

A slight variation on your second scenario is parallel construction.
I don't know if Luigi's the shooter or not, but if he did it, there's a decent chance whatever is presented as evidence has absolutely nothing to do with how they actually caught the guy.

Luigi did it, and he really was that stupid.

Given that he was valedictorian at his school, I find that unlikely to be the option.

I think you're missing a 4th option:

• He did it, and believed it not worth the anxiety/suffering of living the rest of his life as a wanted man, so did what he could to get away from the immediate scene but ultimately turn himself in so to speak.

And there are almost certainly more nuanced options out there.

It doesn't have to have been effective. They might just have overestimated how many people would think killing health insurance CEOs was unacceptable.