Adding people to my mafia in Mafia Wars on Facebook?

I became a fan of Mafia Wars earlier today. Then, I got a friend request from somebody and they put “Mafia Wars” in the message. The problem is that I have no idea who this person is. So, is there a way to add this person to my mafia without this person being one of my friends on Facebook? I don’t want this person to be able to see what is on my wall and that kind of stuff. Any advice will be greatly appreciated.