I read the game in question. Hammering the wrong person in a 3-way lylo is always very difficult. What I like to do is ask questions to the other two. "Why do you think the mafia killed that person?" or "What makes you FOS the other guy?" The more they talk, the more you have to work with. See who tries to buddy, and who is genuinely trying to figure out who the real mafia is.
I'm not mad you lynched me, but I am mad that you did it without so much as a word as to why and wouldn't listen to anything I said in my defense while the mafia lurked their way to victory. Learn to play.