Ok, heres evidence from the other games:

In the Godfather, after Gorebag didn't send in his kill, GeneralH remarked:

Quote Originally Posted by GH
I don't know, let's think about this.

If B_Ray knew Sigurd was a mafioso and knew full well that there would only be one kill the next round, why on earth would he link himself to his now-dead comrade? No way a mafioso would be this stupid.

Either there are two options: The other mafioso probably voted for Reenk or Disco (pretty much anyone but Sigurd), or someone didn't send in their kill in on time.
GH later reflected:

GoreBag missed his kill for the second round. At first I was annoyed, and posted something along the lines of "a mafioso might not have gotten his kill in on time." Luckily nobody noticed.
This is a pretty direct example.

However, other examples of this kind of thing:

Quote Originally Posted by Ignoramus
Wouldn't it be great if GH is the detective? If he is, then we have a living detective all game.
Ignoramus is the detective, wishing he had been elected Chief of Police.

Quote Originally Posted by Dutch Guy
It appears that at least Tiberius was saved, and I'd say the same would count for DA (beer stolen ?). Maybe the work of a lifesaver ?

EDIT: Lifesaver may be a bad word, Doctor would be better
Dutch guy was a doctor.

Quote Originally Posted by Reenk Roink
I don't think you peeples should judge the guy who was at Orb's house so harshly. I mean come on, "thief" is just not right at all. This guy probably is dirt poor, and needs to live on what others waste. If the world were a more generous and fair place, he wouldn't have to go through others trash. Heck, he probably only took the newspapers to use as bedsheets, and also to rummage through the classifieds. Not only that, but this guy chose the right house and gave us an incredible clue on who the real criminals are. And yet he is demonized...

This guy is a hero!

Society has failed this noble, noble individual...
Reenk Roink was the "thief"


I'm willing to bet the mafia is at their most careless at the beginning of the game. I believe that was a slip up by Drisos.

Masy's posting time/Kill posting delay is also worth looking at in the future.