In recalling the events of Laius 'death, Sophocles blames Oedipus' character. That's because, Oedipus' memory doesn't let him escape the guilt over his father's murder. This means that he has no way to deny what he did, because his own mind shows that he is the murderer. In this way, Sophocles allows Oedipus to become a self-tortured soul, as his thoughts return to that memory and do not allow him to free himself from guilt, which makes Oedipus look for punishment himself.