This is the 5th time I read this, and I still can't think of anything :/

Hey, stop twisting my quotes. :-p

Yeah, this is what we figured.

Buckra, I am not sure about at all. Could mean all the people you mentioned, but Sophia already has nick, so I doubt it's she.

Your attention please!

When the game is solved please remind me that I have a confession to make ;) That's something really funny.

As for now let us assume that you were able to crack a few more lines from McCrary's diary:
- I can't believe Spik has a crush on her!
- He knows too much. Somebody will have to kill him when I am not here. could do it but I'm not sure... it's too risky!
- I'm sure that Cheapskate would kill somebody if that was profitable. Interesting...
- I will not let some Sugar take over my place!
- Mr. Vampire. Always hiding. Always watching. Always ready to act!
- I'm not sure if I've ever seen somebody washing his hands as carefully as Non-Kevin does. Amusing.

Once again I'm really sorry for this. It could have been confusing. I hope there won't be any problems now but just in case - do not hesitate to ask if something is not clear.

Oh, and I'll add those additional lines to OP too.

OK, so I looked up Spik and it's term for Mexicans, so apparently Miguel actually likes Sophia.
Second line probably talks about Dennis.
Cheapskate could be Sophia as financial supervisor, but I am unsure about this one.
Suger should be Scott Kanes. As Sugarcane.
Mr. Vampire could be Jacob, as he was hiding in the shadows when he saw Miguel and Sophia talking.
Non-Kevin is Roy Spacey. He is Spacey, but not Kevin Spacey (actor), so he is non-Kevin. It could mean he is telling true and was really in the restrooms until everybody left as it took him long itme to wash himself.

Right now I think it could be Sophia and Miguel together, but it's more of sudden idea, then hard conviction.
Or Scott Kane, but that's unlikely. :-)

Let's get it straight: in real life you have the ability to check everything you want, here you have to rely on a few things you were given so we must accept some sort of simplification so when I said that there are only four people who have the access to the building that means the murderer is one of them.

As for the rest... I like the way you think but you have... well, let Kevin Spacey deliver this advise personally :)

BUMP!

Be sure to check out those additional hints

He's (probably) also Big Jaw (chewing gum) and maybe Wisdom ('Big Jaw is smart.')

Yeah, he should be Big Jaw, but Wisdom is likely Sophia White. See Spinorial's post. (Sophia=Wisdom)

I am bit stuck and I would need someone to at least speculate on the events.

Yeah, well. I have basically zero time to dedicate to it, but, indeed, I don't see why all of you focus on the guy's journal. Facts are a bit more important, and if you want to prove something, it's where you should look.

I'll just copy/paste some notes that I had taken in the first hours of the thread, and add a few comments, and my suspect.

________________________

Sophia's version :
Sophia white goes to the room's doors
She is stopped in front of them by Miguel Rodrigues
She is dragged back down the corridor
They are joined there by Jacob Ward

Roy's version :
Roy Spacey is near the door
He hears Sophia and Miguel
Then he hears Jacob
Then he hears nobody
and he sees that they are all gone

Jacob's version :
Jacob Ward stood "in the dark" ?
Sophia came to the doors
She was stopped there by Miguel Rodrigues
Jacob approaches them (still near the door or not ?)

SO TWO VERSIONS OF THE EVENTS

1) Miguel dragged Sophia away from the door, Jacob joins them down the hall
S- It is sophia's version
R- However Roy hears Jacob as if he joins them, but before walking down the corridor
J- Jacob is unclear, stood in the dark(?) and approached them. Miguel had 'stopped her' (and that's all?).

2) Miguel and Sophia discussed near the door, Jacob joined them here
S- Sophia contradicts this : Miguel dragged her away, Jacob joined them there.
R- Roy hears them all from the WC, although they are gone when he opens the door.
J- Jacob is unclear, but, without any precision, one would assume they stayed at the door.

Less (apparent) contradictions if Sophia lies, but she seems to be the one with the lesser motive to do so (while, for instance, Roy or Jacob could have sneaked into the room while Sophia and Miguel are at the other side of the corridor).

_________________________

I hadn't pinpointed any conclusive contradiction yet, or singled out a liar and his motive (to lie), and his modus operandi. I did suspect Roy and Jacob mainly, for the opportunity given by Miguel and Sophia, if Sophia's story is correct.

But, if we take things at a formal logic level, ditching assumptions and implications for purely formal mathematical enunciations (but this is NOT how language and communication works), then I'd say Roy is the liar and the killer. Jacob is merely unspecific about movements (but when you don't mention movements, especially in such contexts, you usually implicitely communicate statism), but Roy is specific about statism (before Jacob's arrival : contradiction) yet confirms movement (after Jacob's arrival : else they would have seen him open the WC door).

So, my conviction is that Roy is the killer. Maybe more precise proofs are needed, and I'll look for them later. And maybe there's something interesting to compute by adding this element to the cryptic notes of McCrary.

Okay. I thought that "and forced me to walk down the hall" would have implied that they both walked farther than the hearing range of the WC...

But it was not what I meant... perhaps I should have phrased it somehow differently. Once again sorry for the confusion.

Er... Bump?

It would amuse me if Sophia was chewing a gum during her deposition.

ANYWAY

It could not be Sophia IF Jacob is meaning the same door as her. "I saw all of them around this room. Roy went to the toilet which is right next to this door. Sophia was going there but Miguel came out and stopped her." Where was Sophia going ? I assumed to "this room", but the precise preceeding sentence mentions the toilets. so it could be misleading. It's no direct contradiction, and no real confirmation. As for Miguel, he also "came out" from an unspecified location, but if it was the toilets, I assume that he or Roy would have mentionned it. So, depending on these ambiguities, Sophie could have been walking towards the toilets, from the corridor or from the room, in which case, possibly followed by Miguel, or not. Common language is based on implicit elements, that are absurd to question. But, in the context of a game...?

It could be Jacob as his "in the dark" is unclear. Nobody knows from what direction he came.

It could be Roy sneaking out of the toilet after the three others went down the corridor a bit. But yeah, non-Kevin spends a lot of time washing his hands anyway.

I hadn't paid attention to the missing bubblegum, because I assumed that the dépositions were made long after the crime, so that loss couldn't be much related. Yet it was specifically mentionned. Did the described even take place "within chewing time", implying a contradiction between Sophia's testimony and Miguel ? This would mean that Sophia hasn't actually seen Miguel, but this clashes with both her and Jacob's testimony, and Roy's too. And I don't see any point in lying about the gum specifically (apart from a default description if she hadn't seen him). So, was the gum lost aterwards ? How relevant -to what- could this then be ?

All this to say : bump. Without much progression.

Whoa, I totally forgot about it, Sorry! I'll think about a proper hint but I'll add it not sooner than tomorrow.