First and last stories - Leitmotif

Rating: 8/10 (15 August 2005)

Not having read the comics I don't know what may be otherwise well known, but here goes: What is the meaning of the first and final segments? The hit-man has no other bearing in the movie. He seems to be another story that will/might be developed in a sequel. Or...
All the stories (including first and last) carry one leitmotif: Roark. There are time/place coincidences in the three main stories (Hartigan goes to find Nancy in the same bar where Marv is, When Marv arrives to at the house where Kevin is, he hears someone hitting someone else in the top floor: that later turns out to be Roark Jr. lashing Nancy, etc). But in the first and last stories, there is no such coincidence. What seems to connect them to the other three is the underlying evil in Sin City. As a Senator/Cardinal/Degenerate, Roark is the personification of that evil power in Sin City and (probably) also whoever hired the assassin both times.
Do the comics clear this up or do they also have -on purpose- loose ends like this one?