You meet six men on a road side. The problem is that your wallet is mysteriously missing and you can't figure out if these men are truth tellers or not. So you ask a few questions and here are their answers:
Allan: "Fred stole it. Fred also hears quite well."
Barry: "Calvin is a liar. I did not steal it and I know Allan did not steal it."
Calvin: "Allan and Dwayne are both knights. Eddy stole it."
Dwayne: "Allan is a liar. I did not steal it."
Eddy: "Only 4 of us are knights. I did not steal it. I know Calvin did not steal it."
Fred: "I am deaf but read lips. Barry did not steal it."
Who stole the wallet?
P.S. You are sure that all of the men either lie or tell the truth. No one does both.
If A told the truth, then F stole it, and hears well; since F says he is deaf, then he lies, and therefore B was the thief -- we'd have two thieves!
Thus, A lies, so F is deaf and innocent. F says he is deaf, so he tells the truth, and thus B is innocent as well.
D said A lies, so D tells the truth, and is thus innocent.
C said A told the truth, so he lies, and thus E is also innocent.
E said he wasn't guilty, so he tells the truth, and so C isn't guilty either.
B said C lied, so he tells the truth, and so A is also innocent!
In conclusion, nobody stole the wallet!