The Spiral Bridge — Alvin H. Franzmeier

Little does Tillie Tilden, a Depression-era college student, realize what she is stepping into when she accepts an emergency teaching position in a southern Minnesota country school at the end of her junior year. For some strange reason, the people of this tiny rural village do not want to discuss what happened to the previous school teacher. Eventually Tillie discovers that she committed suicide because of an unwanted pregnancy. The doubts remain, however. Was it suicide or was it murder? The following spring, Tillie discovers the former teacher's diary hidden in the wood storage room of her one-room school building. This discovery leads her to suspect murder, possibly by her own school district superintendent, the teacher's uncle. As the school year ends, Tillie discovers who the killer is and in the process is nearly murdered herself.