An inhabitant has been killed in Knavesville and the Sheriff has interrogated four suspects. It is known that one of them is the killer. As is expected of Knaves, they alternated between telling the truth and lying (Not necessarily in that order).

Each suspect was first asked if he was the killer, to which the sheriff got the same answer from all the four suspects.

He then asked them, 'Who was the killer?' The answers to which are shown below.

Abbey said: Bart is the killer.
Bart said: Dean is the killer.
Cody said: Bart is lying when he says Dean is the killer.
Dean said: If Abbey did not kill him, then Bart did.

Who was the killer?

I believe Dean is the killer.

Either 3 are lying and 1 is truthful, or 1 is thruthful and 3 are lying.

If Bart is thruthful and all the others are lying, there are no contradictions: Abbey is lying, because Bart is not the murderer.

Cody is lying, because he is saying Bart is lying, and Bart is actually being truthful.

Dean is lying, because neither Abbey nor Bart killed the man.

If Bart is truthful and Dean is the killer, there are no contradictions, therefore Dean is the killer.

Posted by Tweedy on 2007-03-12 17:46:18