A lady and her husband move in to her sick/dying dads house. Their neighbors houses are all empty because it’s winter where they are and it’s like a vacation town. She sees light on at neighbors house and walks through a path to the backyard to investigate. They eventually find a woman living there in the house. Theirs an aspect about money and the girl not being able to leave? Or she’s paid to be there? The ladies husband has sex with the woman and it’s like a whole big deal (obviously). I can’t remember how it ends but i wanna say the husband kills everyone? Or something to that effect. I found this book at a yard sale maybe 3-4 years ago and read it then donated it. It was probably my favorite mystery book and i want to read again. Any help appreciated!