Ref this question
Here's some info from a very good friend who retired from RSO:
"Here is the best case assumption on the transmission your friend heard. This info comes from a patrol deputy. Nora Exceptional is still around. His best guess, (and mine) is that the Dep was assigned to do a followup on a case that had already been assigned a file number. Does not happen often, however, sometimes additional information becomes available from a victim/witness on a subsequent shift. Most often this add'l info is just taken by a Dispatcher, or the calling party is just told to call their info into Investigations the next morning. In this case it sounds like the add'l info merited actually sending a Dep to make contact. Since a file number had already been assigned he should have just cleared as "10/98 followup." Don't know why they called it "FU", or maybe that's what they're calling it nowadays, (bet there would be a lot of inappropriate radio traffic using "FU") Hope this helps. Also sounds like the Sgt was talking to a new Dep."
