It depends. Sometimes books with nefarious plots are inspired by real events, but they often incorporate fictional elements to make the story more compelling.
One such book could be 'In Cold Blood' by Truman Capote. It is based on a true story of a brutal murder in Kansas. The book delves deep into the minds of the killers and the events that led to the heinous crime, showing a real - life nefarious plot.
The fact that it's based on a true story. People are often intrigued by real - life events, especially when they involve a nefarious plot. It gives a sense of authenticity that fiction sometimes lacks.