History of the Peloponnesian War

Hippias, after reigning three years longer over the Athenians was deposed in the fourth by the Lacedaemonians and the banished Alcmaeonidae, and went with a safe conduct to Sigeum, and to Aeantides at Lampsacus, and from thence to King Darius; from whose court he set out twenty years after, in his old age, and came with the Medes to Marathon.

With these events in their minds, and recalling everything they knew by hearsay on the subject, the Athenian people grew difficult of humour and suspicious of the persons charged in the affair of the mysteries, and persuaded that all that had taken place was part of an oligarchical and monarchical conspiracy.

In the state of irritation thus produced, many persons of consideration had been already thrown into prison, and far from showing any signs of abating, public feeling grew daily more savage, and more arrests were made; until at last one of those in custody, thought to be the most guilty of all, was induced by a fellow-prisoner to make a revelation, whether true or not is a matter on which there are two opinions, no one having been able, either then or since, to say for certain who did the deed.

However this may be, the other found arguments to persuade him, that even if he had not done it, he ought to save himself by gaining a promise of impunity, and free the state of its present suspicions; as he would be surer of safety if he confessed after promise of impunity than if he denied and were brought to trial.