There are two versions of Laius’ murder in Oedipus Rex. First, there is the version that is current in Thebes and is expressed by Creon, Jocasta, the Chorus, and presumably the Shepherd if he were to talk about it. Second, there is Oedipus’ version.
The first version is essentially this: one day, not too long before the Sphinx came to terrorize Thebes, Laius set out—so he said—to Delphi. He did not travel as a king generally might with a great many soldiers, but with only four of his men, one of whom was a herald. Laius himself rode in a chariot. At a place where three roads meet, Laius was met by a group of robbers.