You Will Never Know by S. A. Prentiss

Blended families can be difficult as one set of parents/stepparents discover after one of the teen's classmates is murdered. Jessica will do anything to keep her daughter's rise to track glory on the right path. Ted wants the best for his son. Stepbrother and stepsister can't stand each other but find themselves in an uneasy alliance. One murder will uncover too many secrets that no one was ready to reveal. A twisty plot with really unreliable witnesses and alibis with more holes than Swiss cheese.  3 1/2 stars