How explicitly does the prophet Teiresias reveal the guilt of Oedipus?
Oedipus is eager to learn the identity of the murderer of Laius, because Creon has informed him that the plague that has befallen Thebes will be lifted only when the murderer is brought to justice. He knows that Teiresias, the blind prophet, knows the identity of the murderer, and summons him to reveal it. He asks him to "save thyself, thy country, and thy king" by identifying the murderer. The blind seer, knowing the terrible reality, demurs, observing that it is is "misery to be wise when wisdom profits nothing." Oedipus challenges his sense of patriotism, beseeching him to reveal his wisdom on the matter, but Teiresias still holds out.
Only when Oedipus, outraged and frustrated, accuses him of plotting the murder, does the prophet give in. He says "Thou art the man / Thou the accursed polluter of this land." When Oedipus, stunned, demands that he repeat himself, he says explicitly that Oedipus himself is the "murderer of the man / whose murderer thou pursuest." He then explains that Oedipus "livest with thy nearest kin / in infamy, unwitting in thy shame." Oedipus is outraged, and blames Creon for basically putting Teiresias up to the prophecy, if not plotting against Laius himself. Teiresias tells him that he is his own "bane," and that he "unwitting . . . [is] a double foe" to his family. Eventually Oedipus will learn the horrible truth, but at this point in the play he dismisses Teiresias for his "insolence," even though he only very reluctantly replied to Oedipus's repeated queries. He did not tell him the "back story" to how he became the killer, but he explicitly told him that he was the man responsible.
When Teiresias is first summoned by Oedipus, he is very hestiant to speak. His first comments to Oedipus are vague at best. Teiresias seems to avoid the questions asked, telling Oedipus to let go of this search, and that it will bring him nothing but pain. Oedipus continues to press Teiresias, however, essentially accusing him of being a traitor to his people. Oedipus believes that Teiresias knows who murdered the former king and is enraged that the prophet would let innocent people suffer rather than reveal the murderer. After being pushed and prodded by Oedipus, Teiresias very bluntly says that Oedipus is the murderer they seek.