Secret Sisters by Jayne Ann Krentz

Secret Sisters - When Madeline Chase was 12, she was attacked at the hotel her grandma, Edith Chase, owned and operated.  Her best friend, Daphne Knight was able to raise the alarm and Edith; Clara Knight, Daphne's mother; and Tom Lomax, the caretaker, saved Madeline.  But, the five had buried a secret that was now coming back to haunt them.  Edith is dead and Madeline finds Tom dying in the lobby of the abandoned hotel.  Madeline calls her security adviser, Jack Rayner, who when they realize that the deaths have something to do with that long ago incident, has his brother and employee, Abe Rayner pick up Daphne.  The four then begin to investigate not only Tom and Edith's death which leads them to the island's leading family, the Websters.