Same here.  I figure it could be either the firefighters or FOP as they are the most frequent callers from this part of NC but can't know for sure as they don't identify themselves.  I received a call from a close town that never left messages either and I blocked them after they called me 9 times in 5 hours.  I suspect that was just a prank.  If this number harasses me, too, I'll block it also.  I don't answer unknown numbers especially when they refuse to identify themselves.