Media are rife with haunting stories of true crime, but some accounts are more chilling than others—particularly those that involve torture and murder. In If You Tell, Gregg Olsen recounts the story of notorious abuser and murderer Shelly Knotek, who, along with her husband Dave, abused and tortured their daughters, nephew, and two boarders—resulting in three deaths. Olsen is a best-selling true crime author and novelist who was asked to write this story by the Knotek daughters themselves.

In our guide, we'll discuss the ways in which Shelly abused her victims along with Dave’s help. We’ll also look specifically at how she lured two friends to become boarders at her home and then killed them, and we’ll look at the events leading up to Shelly and Dave’s arrests and convictions. Additionally, we’ll add information about the psychology of abuse and psychopathy, compare it to similar stories of child abuse, and add context about the legal system and its responsibilities in cases like these.