Any novel needs dramatic tension, but mysteries and thrillers need it even more than most. Tension, something unresolved and threatening to an important character, will keep the reader turning the pages. If the writer resolves the tension too quickly, he has lost an opportunity to sustain reader interest.
In the case of Empty Luck, the story I am currently writing, one of the characters steals money from a dangerous individual. In the very next chapter, he is caught by that individual. I realized that was premature and had I left it in, I would have missed a chance to capture my readers’ interest and emotional involvement.
So instead, I deleted that next chapter and left the situation hanging, open and threatening to my thief. Will he get caught? What will happen to him? No need to give this away too soon. That is dramatic tension. And the tension is still greater to the extent the reader cares about the threatened character.
It’s easy to sacrifice tension in the service of moving to the next development in the plot, but that is usually a mistake. Better to step off to the side with a sub-plot or simply to put more obstacles in the path of the resolution of the situation and actually increase the tension even further that way. I don’t think there is such a thing as too much tension.