Greg Cox wrote:
I guess what's unusual here is that we're used to seeing the character of Moriarty introduced at a point when Holmes is already aware of him and has been tracking him for some time -- but here we're coming in on the ground floor, seeing the moment when Holmes first became aware of a shadowy criminal mastermind.
Exactly. At this point, pretty much everything Holmes knows about Moriarity is a name on an index card, surrounded by a lot of empty space. As represented by that final scene.
Moriarity (whomever he or she is) has obviously been aware of Holmes for some time, but Holmes only just now became aware of Moriarity's existence.
Well Sherlock did say he had been assisting Scotland Yard for quite awhile in tracking down M, so I assumed he would have pieced together at least a little
more by now (even with all the rampant drug use).
Hell, just the fact he was able to elude Sherlock for this long
should have made it clear that this was no normal, everyday killer.