Hope, take the call. For some reason there's a person making that call.
Maybe Bill is at his family members house, has no computer access anymore and/or wishes to communicate, by phone and thought he would look you up while in Denver.
Things do happen, not all good, but this one could be a good one. I know I have lost information and slacked in trying to relocate it, when I do, then I tend to put things off.
Perhaps he didn't leave a message since he didn't know who, for sure, he was supposed to communicate with, if it wasn't Bill himself.
Maybe he lost his info, had something written down somewhere, found it and tried to call.
Make that connection with Nathan Thornton, it could be the call you need to receive.
I'll be checking back in a few days, gotta run now ( I wish I could run ) but I'll be interested in that Nathan/Bill phone message. I hope he tries again.