No Mourners For Victoria

Frances Finn is a college English instructor married to a detective lieutenant in the homicide division of the Los Angeles Police Department. When she is not reading 'great books' for the courses she teaches, her favorite recreation is reading whodunits. This sometimes causes her to take an inordinate interest in her husband's homicide cases, much to the distress of Marco, her husband.
Imagine her delight, then, when she is invited by an old college acquaintance, who is quite wealthy, to spend a week at one of the most exclusive spas in southern California, along with some of her other friends from her college days - a sort of reunion after ten years. She envisions sitting by the pool, eating healthy food, sipping vegetable juices while reading the pillowcase full of mystery novels.
It doesn't quite turn out that way, far from it. She immediately becomes involved in the death of her hostess, and, before the week is finished, is involved in subsequent deaths. Her Miss Marple instincts cause her to be part of the investigation, in which she plays a key part in solving - including a near-death encounter with the murderer.