So I have pieced together some information regarding the new Hunt The Truth marketing campaign. This Benjamin Giraud is for certain the person interviewing Halsey in the beginning of Halo 4. I believe this interview takes place between the end of The Next 72 Hours and the Spartan Ops Arc. This is possible since Halsey is still a prisoner and Giraud has access to interview people like her. We could possibly hear more about this more in the upcoming weeks with the other Hunt The Truth audio files.