(And somewhere in the back of his mind was a small, small note of confusion, a sense of something wrong about that story; and it should have been a part of Harry's art to notice that tiny note, but he was distracted. For it is a sad rule that whenever you are most in need of your art as a rationalist, that is when you are most likely to forget it.)
Why does the wizarding world believe Voldemort used the Killing Curse on Harry? Whether or not the Love Shield exists in MoR, I doubt most wizards had an >epsilon prior for the Killing Curse resulting in a scarred but otherwise unharmed target, a dead and burned spellcaster, and a destroyed building. There were no surviving witnesses except Baby Harry. Where did that version of events come from?
If I was Joe Random Wizard and heard that evidence without names attached, I would naively hypothesize: Dark Wizard shows up at house, encounters mother + father + their allies. Battle ensues. Parents and Dark Wizard are slain. House is destroyed and baby is hit by debris. There is one obvious question - why the allies didn't take the baby with them - but any answer to that is more plausible than "There were no allies; the most reliable curse in the world backfired on its most experienced practitioner."
Not that the "reflected curse" story was hard to sell. People are great at not asking the next question when they want to believe.
We have some additional information about the events of that evening:
- Harry's memory under Dementation (Ch43). This may or may not be a true memory.
- Snape relayed the complete prophecy to Voldemort without understanding it (Ch77). McGonagall was the propechy's witness (Ch28), but Snape has also heard the original audio (Ch77).
- McGonagall knows that Voldemort is still around (Ch6).
- Quirrellmort does not want to kill Harry. If he ever did, he changed his mind while offscreen.
What really happened at Godric's Hollow?
PS. If the Love Shield does exist in MoR, do you suppose Bellatrix could cast it?
That spell is canon. In the fourth book, HP & the Goblet of Fire, they use the Priori Icantato spell to try and determine who cast the Dark Mark. There's also legilimens, the spell used to look into another's mind. Using just these two spells, you can set up a reasonable course of events.
Presumably, forensics arrives on the scene and sees the destruction. There's a set of Voldemort's robes on the ground along with his wand (NB: you never ever part with your wand). There's a dead Lily and James Potter, along with a baby with an odd looking scar. First thing's first, they examine the wand, confirm it's Voldemort's and reveal that the last spells were 3x Killing Curse. Next they look at the baby and extract it's memories, showing what just happened. Then they check any recording devices in the house, and look at the state of footprints, wards, etc. showing who came and went. Finally, Snape talks to Dumbledore and with that information they put together the pieces of why the Dark Lord went there that night.
People cheer and declare that Harry Potter Day! The upper echelons aren't convinced. To use a chess metaphor, perhaps the Dark Lord merely pretended to open up his queen to bait a checkmait. But then the Dark Lord still never returns. His inner circle is taken down, captured death eaters are in disarray. His artifacts and strongholds are taken. Clearly, they reason, he must be dead. There's no reason for his absence except for his destruction. One does not sacrifice every piece on the board for any gambit, no matter how clever.
A few people still hold onto the alternate hypothesis that the Dark Lord faked his death, but that is considered a crackpot theory. Why would the Dark Lord disappear and let his fledgling empire crumble into ruin? Why would the Dark Lord leave his wand? Why would the Dark Lord go through an elaborate hoax on what is seemingly a routine hit mission? What possible plot would involve him disappearing from the face of the earth for ten years? The 'Dark Lord still lives!' crackpots would be the equivalent of 9/11 Truthers of the magical world. Those who believe in his death are the rational ones.
It's merely confirmation bias that makes it seem so obvious to us.
In Summation, the strongest evidence for that night isn't the magic. That is quite costly but easily faked. The best evidence for his death is in his absence for over a decade.
I don't have time to check the MoR archives, but didn't Bellatrix retrieve the wand? Or did Voldemort give it to her before he went to Godric's Hollow and just take another wand?