Xack 'The Knife,' the ill-famed tough guy, was found murdered on a particular night in a pathway behind the discotheque he frequently visited. The police brought in three suspects on the next morning. A detective was called who interrogated the three men and noted down the following statements given by the suspects.
Richard:
1. I did not kill Xack.
2. Morgan is not my friend.
3. I knew Xack.
Morgan:
1. I did not kill Xack.
2. Richard and Travis are friends of mine.
3. Richard did not kill Xack.
Travis:
1. I did not kill Xack.
2. Richard lied when he said that Morgan was not his friend.
3. I do not know who killed Xack.
One of them has actually killed Xack 'the knife'. Can you find out who is the killer?
Solution:
It is not Richard because if it was, Richard 1 and Morgan 3 would both be false, which would make Richard 2 and Morgan 2 both true which is a contradiction.
It is not Travis because if it was, Travis 1 and Travis 3 would both be false, which is not possible.
Therefore, the killer must be Morgan.