"Watchman, old man, I believe somebody is murdered down the street."

[Lechmere]

Steady on Monty

[Ginger]

I'm left wondering why the Whitechapel District Board of Works would employ a night watchman to stand guard over a sewage works.

I've always taken it to mean that some work was being done on the sewers, and probably supplies, workmen's tools, etc., were left there overnight, and needed to be watched.

[Barnaby]

Complete aside: My 4-year-old stands guard over every drainage ditch/pipe/gutter he finds: The Ninja turtles are down there.

Related: My gut feeling is that a serial killer who poses the victims would be much more likely to interject himself into the case. Is this backed up with data (too lazy to look - busy watching out for Shredder coming out of the sewer).