Oedipus does not realize that he is the murderer and takes an oath that he will indeed bring this murderer to justice in order to save the city. The audience already knows who the killer is but the actors have no idea and the plot thickens. As the piece progresses, the chorus serves as a reminder of how there are so many deaths due to the plague. This is an opportunity to help the public imagine the severity of the plague on the city. What you have to imagine is that there are corpses and rotting corpses everywhere. The plague is not caused by something that can be transmitted by casual contact but by an act of murder. Praying to the gods will do no good because the message is clear, kill Laius' murderer and the plague will disappear. Oedipus offers a reward to anyone who knows about the murder of King Laius. When no one comes forward, he curses them (unknowingly cursing himself). He summons the blind seer Tiresias to help him find out who killed Laius, but Tiresias refuses to divulge what he knows. After much insistence, Teiresias reveals that Oedipus himself is indeed the killer they are looking for. After debating with Tiresias whether or not he is telling the truth that Oedipus is the murderer or whether Creon caused Tiresias to say that Oedipus killed Laius..