This item is a novel by Mary Higgins Clark, 'Nighttime is My Time'.
Jean Sheridan, a college dean and prominent historian, sets out to her hometown in Cornwall-on-Hudson, New York, to attend the twenty-year reunion of alumni of Stonecroft Academy, where she is to be honored along with six other members of her class. There is, however, something uneasy in the air: one woman in the group about to be feted, Alison Kendall, a beautiful, high powered Hollywood agent, died just a few days before, drowned in her pool during an early-morning swim, the fifth woman in the class whose life has come to a sudden, mysterious end.........