Which character serves as a witness to Laius's murder and becomes crucial in Oedipus’ investigation?

The servant of Laius is pivotal in the unraveling of the murder mystery surrounding Laius's death. He is the sole witness to the events leading up to the murder and possesses vital information that can help Oedipus piece together what happened. His testimony provides the necessary details that can confirm Oedipus's fears and guide the investigation into the truth of Laius's death. This connection to the murder makes him crucial to Oedipus’s quest for knowledge about his past and the unfolding of the tragic events that lead to the revelation of his own identity and actions.

In contrast, the priest of Apollo serves more as a spiritual advisor and has a role in emphasizing the moral and religious implications of the tragedy, while Creon’s role is more politically oriented as he interacts with Oedipus regarding the plague in Thebes. The messenger from Corinth mostly brings news about Oedipus's lineage, but does not hold key information about the murder itself. Thus, the servant's direct experience makes him an essential character in Oedipus's investigation.