Antiphon, Against the Stepmother for Poisoning
K. J. Maidment, Ed.

[6] Further, it is not for my brother to say that he is quite sure his mother did not murder our father for when he had the chance of making sure, by torture, he refused it; he showed readiness only for those modes of inquiry which could yield no certainty. Yet he ought to have been ready to do what I in fact challenged him to do, so that an honest investigation of the facts might have been possible;