Fool Her Once by Marcy McCreary

In the waning days of the Catskills hotel era, Stanley and Rachel Roth, the owners of The Cuttman Hotel, were practically dynasty-third generation proprietors of a sprawling resort with a grand reputation. The glamorous and gregarious matriarch, Rachel. The cunning and successful businessman, Stan. Four beautiful children. A perfect family deserving of respect and loyalty. Or so it seemed.
Fast forward forty years. The Roths have lost their clout. When skeletal remains are found on the side of the road, the disappearance of Trudy Solomon, a coffee shop waitress at the Cuttman in 1978, is reopened. Each member of the Roth family holds a clue to the case, but getting them to admit what they know will force Detective Susan Ford to face a family she'd hoped never to see again.