M. Tullius Cicero Pro P. Sulla 39

[39] But I think that, in judicial proceedings and examinations, the thing to be inquired is, not whether any one is exculpated, but whether any one is inculpated. And in truth, when Cassius says that he does not know, is he seeking to exculpate Sulla, or proving clearly enough that he really does not know? He is unwilling to compromise him with the Gauls. Why so? That they may not mention him in their information? what? If he had supposed that there was any danger of their ever giving any information at all, would he have made that confession respecting himself? He did not know it. I suppose, O judges, Sulla was the only person about whom Cassius was kept in the dark. For he certainly was well informed about every one else; and it was thoroughly proved that a great deal of the conspiracy was hatched at his house. As he did not like to deny that Sulla made one of the conspirators, his object being to give the Gauls as much hope as possible, and as he did not venture to assert what was absolutely false, he said that he did not know. But this is quite evident, that as he, who knew the truth about every one, said that he did not know about Sulla, the same weight is due to this denial of his as if he had said that be did know that he had nothing to do with the conspiracy. For when it is perfectly certain that a man is acquainted with all the conspirators, his ignorance of any one ought to be considered an acquittal of him. But I am not asking now whether Cassius acquits Sulla; this is quite sufficient for me, that there is not one word to implicate Sulla in the whole information of the Allobroges.