Good article Dave, one thing I was curious about though was the obvious population difference between Seattle and Chicago. So I did a little math.
594,210 Seattle's approximate population
2,836,658 Chicago's approximate population
Chicago's population is @ 4.77 times that of Seattle. Even if we multiple Seattle's murders by the population difference we get 133.56. that's still almost 1/4 that of Chicago's 509 homicides. (3.8)
Of course this was just a quick look at figures and not an in depth study.