I think this is important to this case. Her sister reported them missing, and I would bet this is something he didn't think would happen before he came back home.
Susan and her sister must be very close for her to call and make a report after 1 day. Did she hear from someone that Susan works with that she didn't show up for work on Monday? Did she try to call Josh's cell phone along with her sister's? It seems apparent that her sister felt something was really amiss to call and report this so soon as a missing person. Did she know a lot of Susan's marriage that was going wrong that she was immediately suspicious to call LE and report this?
Just thinking out loud.........