Great question. I’ll take it in two parts.
In general, the value of visiting a book’s setting(s) was something I underestimated early in my writing career. And my first two (unpublished) novels show it. There’s something about being there that makes the writing more authentic and therefore convincing. When I write now, I make every effort I can to see places for myself. I spend a bit of time, take in the surroundings and jot down specific things that that are both unique and interesting. You just can’t get that sort of stuff from Google Maps. I run through all five senses individually, and I always get more material than I end up using in the book.
Specific to The Hubley Case, the locations weren’t chosen as creatively as one might think or perhaps as I would like. Instead, it was pretty straightforward and logical. I knew I wanted the primary setting to be the Chicago area because that’s where I live. And I knew I wanted Peter Hubley’s murder to occur on foreign soil, because it added to the mystique, RE: the FBI’s involvement. As it happened, my job as an International Program Manager brought me to Brazil several times during the time I was thinking through ideas for the book, so it seemed like a great location to use. Seeing all the cities firsthand and interacting with the wonderful people who live there allowed me to get a solid grasp of the environments and communities.
Fun fact: I was actually sitting in GRU international airport when the idea for the massacre of a seemingly innocent businessman first entered my mind.