Oh hi Guy, taking a break from Burk's story?
The murder was probably self defence in all honesty.
OK so I think I'm finally getting the timeline right, so Noah's story takes place let's say (with the time it would take to travel and counting how long it took guy to choose which Baron to visit with all the research he would need to do (and because it's easier to think about it when it's an even number)) Burk's story takes place a year after Noah's. Now for Tobi's story it should be several years after Noah's considering in the last page we saw Smile dudes and they looked pretty normal so I believe that the smile corporation mustn't be messing to much with genetics at this point (also they would need time to grow into a well established very dangerous group). So with this we can plot out smile corporation's timeline, Noah: they are a small established group doing weird things, Burk: we haven't caught wind of them but this should be a massive growth spurt period for them, Tobi: they've got a large foothold in dangerous countries of the world where even powerful gangs and government police fear them.
'The empire is housing a monster' is getting more and more credence with each strip.
The guards are pretty much guaranteed to put a stop to any escape attempts, half baked or otherwise(and if Noah doesn't realise this, Ciel...).
But why is Noah so heavily guarded? Think about it, there are eight pupils in Noah's class alone, there must be dozens of others, some of them fee magic users. Yet, they are guarding Noah around the clock, despite that there are only a dozen or so royal guards. And the guards need time to eat, sleep, be sick and to guard the emperor. Speaking of whom, Noah was sent an invitation letter in his name(he wasn't the only pupil so blessed, but still). And these personal meetings with Vader...
Why is Noah receiving all this attention?
With regards to the timeline, it'd be funny if Noah was the reason a man fell from the sky.
Noah doesn't need a plot shield with so many people concerned about his well-being.
Guy may be working for Veda now (but wasn't before). He most definitely works for Veda when he appears in Burk's story, but when does his allegiance change?
We are almost entirely sure that the murder victim was killed by Veda in self defence, and we know that Veda hasn't reported the incident publicly, but Guy may have switched from investigating the issue to covering it up, and that begins with telling Noah to shush up.
It's more likely that the Joy Cult and the Smile Foundation are completely unrelated.
Of course, the alternative to my idea above is that Guy is pretending to go along with the cover-up, but he's actually going on vacation to investigate the murder without rousing suspicion.
So this leaves us with two archetypes:
Good Cop for the kids, but really just a player in the school's plan.
Rogue Investigator trying to gather enough evidence to blow the whistle.
I never really gave much thought to timeline until someone brought it up. I feel like Neo should chime in on that unless its spoiler to the story
The joy cult and the smile foundation could be sister organizations -- different groups in different places, but with the same people behind both.