There was a kill by two people on N2, and no townies are claiming it, unlike the other kills. That kill is almost certainly mafia,
Mmm, yes, I mentioned this?

which means that there cannot possibly be 4 mafioso in my group.
That doesn't follow. What I'm saying is that it's possible that you as a scum team took credit for the Zack attack; if 5 were to vouch, or 4 with 1 dead even, then that possibility could be ruled out.

plus add on a fifth person so they would know the names of the entire group?
Fictively tack on a 5th, is what I'm getting at. That's why we need everyone's confirmation.