So I've noticed three little tid-bits from the Day post, which may or may not lead us to a possible Mafia.
Firstly was this:
Day Post said:
they apparently know well their enemies
So, I would say that this quote insinuated that the mafia know Christos well, Or one of them does at least. In this way, I feel a member of staff would fit the bill, having worked alongside him and presumably getting to know him. But a member on his friends list would also work too, which doesn't help so much until we begin to do some digging.
The second would be this:
Day post or something said:
a bit theatrical for my taste
This could possibly relate to the Role Playing Theatre, with the theatrical reference, and doubly fits because I've never seen Omi there. Coupled with our first interpretation, this narrows down the list of possible candidates quite significantly. RPT regulars are quite many here, but those on Christos's friend list and who are regulars in RPT aren't that many.
My third idea helps solidify this, in a way:
Erm said:
oh well this story is going to get more interesting it seems
I feel this relates to the developing stories in the RPT, and maybe someone who is part of one, running one? Either way, this gives you something to think about, and solidifies my second point a little.
After cross-checking Christos's and Doof's friends lists, I have found that no one in this mafia is present on both friends lists, besides having each other. Unless Omi was perhaps trying to allude to Doof coming back and being mafia now, I want to turn to looking at the staff now, which would narrow the list down to gimmepie and Mana.
But gimmepie's post incriminating RPT regulars yet pushing attention off himself does make me a little suspicious. As such, I'm going to leave my vote at:
[KILL]:
gimmepie