You're right. I actually got it mixed up with another post Dee made. Post #60, Dee seems to hint that she's open to the idea of there being multi-mafia teams.
I still think this is worth some scrutiny, because at this point in the game there was no real reason to believe that there were multiple killing roles in the game. It was Day 1 after all. I was not grouping people with the intent of suggesting that there were mafia pairs, but three different players seemed to believe I was. Two of those players have been revealed as mafia. If this theory holds any water, it's possible that either Dee or another mafia member picked up on this. That could offer an explanation for how mafia members were killed on two consecutive nights.
It's worth noting that both D'Anna and Athena, who commented on the idea of multiple mafias, ended up actually being mafia members.
Of course, it's totally reasonable to suggest that there's either a Vigilante or a Serial Killer in the game as well. Unfortunately I don't have any information.