I don't know when it happened. I don't read mysteries, as a rule. Once, in a book club, I had to read a compilation of Father Brown stories by G. K. Chesterton. These obscure classics were written between 1910 and 1936 and published as installments in a periodical. The protagonist is a stubby British priest who solves mysteries by observation and mental acuity.
And also by coincidence which--to be honest--plays a part in the resolution of almost all mystery stories. The problem with those little stories is that some critical bit of information was always withheld from the reader, making it next to impossible for the reader to solve the mystery on their own.
Needless to say, that little omission did not make me happy. In fact, it pissed me off.
As humans, we want to figure things out. We like the challenge of being smarter than the hero--or at least as smart as. We want to share that "A-ha!" moment with the characters we have been walking so closely with through the story.
So when I ended up unexpectedly writing mysteries, I knew I couldn't do the same thing to my readers that Chesterton did to his.
Luckily, I'm a plotter. I write my stories in a straight line. That means I can scatter the clues through the story as I write it. Assuming I know what those clues are, of course.
The funny thing is, once I made the decision to write a crime/suspense/mystery story I realized that all of my previous stories encompassed crimes, suspense, or mysteries. I had been doing this all along.
Huh. Who knew.
Anyway, if I think about it, I guess I can trace this all back to my hatred of math. Algebra, to be specific. (And long division. I always hated long division.) But when we got to geometry and proofs, I was in heaven. I thought that finding the steps from here to there--all small steps in the path to the solution--was so much fun!
This wasn't boring old arithmetic, it was a mystery to solve. A puzzle where pre-described steps had to be laid out in a logical sequence in order for the ending to make sense.
So now I see my mysteries as geometric proofs. Little steps which, when connected in the correct order, lead a path to the resolution. This makes the plotting of the crime detection so much easier to structure. And it explains why I was writing them long before I consciously knew what I was doing.
Now that I'm here, I guess the next mystery question is: why is there a dead body behind the study wall?
I'll let you know as soon as I do.