Transcript of audio file:

Seems I'm back where I've started. Don couldn't have been our perp, Bill and I gave this thread case to Chester just last week and according to his neighbor, Rolly, Don's been gone all week building some square in New Orleans. I might be out of players, but I'm not out of the game. I just need one break, and maybe our perp finally gave it to me. The pattern has changed. I didn't get one envelope this time. I got two. And one of them has a lock on it. I'm guessing the key to opening the lock is in this last clue. I'm about to break this case wide open, I can feel it.