Of course I found myself changing the story line as I wrote. Besides that, a buildup to each incident was necessary. I had to weave aspects of my sleuth's life—her friends, family, lover, enemies, and work colleagues—into the plot. All this required on-the-spot writing. Pantser-writing, if you will.
Now that I'm writing under contract, I've discovered that I give a much freer rein to my Pantser side. Of course I work from an outline that includes the theme and subplots of each novel. I know the victim or victims, the suspects and the killer.
In my attempt to keep the story line as vital as possible, I add details and events as I move along, elements I don't anticipate when writing the outline. Recently, I realized that I wanted Carrie, my sleuth, to view a character I had introduced earlier in the book as a possible suspect. To do this, I needed to create a scene that included Carrie, this character and an incident that would make him look suspicious.
"Hurry up and write it!" I told myself.
Nothing came to me.
Fortunately, I decided not to force the issue. I told myself the solution would come to me when it was ready.
And it did! An hour or two later I knew how I was going to reintroduce my suspect. What's more, I had already set the stage for his reentry into the story earlier in the book. I realized that my creative process had been kind enough to do this many, many times in the service of writing many books. I was proud of myself! I didn't panic. I didn't worry that the answer wouldn't come. I trusted myself, the process, and the book I was writing.