Dahlia Case Solved!

And the Connor residence, where the Crazy Times come and inundate like so much floodwater.

Note the map of the area. Looks like, well, the area where one encounters the female pudenda, wouldn’t you say?

Which bears a striking topographical similarity to this area —

conclusively proving that poker-wielding wife beater John D. Spreckles III was the Dahlia killer!

(The street layout also resembles a candelabra, which further serves to implicate Spreckles as a Hebrew. With Yom Kippur just days away, Spreckles was obviously making certain he had plenty to atone for.)