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?

Since Bart and Cody gave conflicting testimonies, one of them must be the killer.  We know then that Bart is lying when he says Dean is the killer, and thus Cody is telling the truth.

If Cody is not the killer, then he would have admitted being the killer at first.  Likewise, if Bart is the killer, then he also would have admitted being the killer at first.  Thus all four admitted to being the killer in response to the first question.

This means that the agreement between Abby and Dean which points to Bart being the  killer is truthful since they both lied at the first question which means that Bart did it.

However, if Cody is the killer, then he would have denied being the killer at first.  Likewise, Bart also would have truthfully denied being the killer.  This is corroborated by the untruthful statements of Abby and Dean accusing Bart, thus implicating Cody.

Edited on March 9, 2007, 1:46 pm

Posted by hoodat on 2007-03-09 13:38:51