Sometimes humor can be suspenseful. Not all suspense is drama. One trick of many authors is to do a quick turn from humor to drama in a sentence. It raises the level of cognitive dissonance i.e. Feeling different things at one time Happy/Sad, Calm/Excited, Relaxed/Alert... and so on.
Another device an author can use to create suspense and throw the reader off is something called a "Red Herring". It's a specific item in a book that seems to have importance to the story but either is dropped and never mentioned again, or its importance to the story is greatly diminished. There is a "Red Herring" in Flesh, Bone, Clone (copyright©2014 Edward R. Murphy) it's an interesting part of the book but not an essential part that the reader is lead to believe.
Keep reading - It was reported today that ebooks have overtaken paper books in sales amount. 52% ebooks vs. 48% paper books.