Death Takes a Hand — Susan Moody

Ex-biology teacher Cassandra Swann turned in her lab coat to pursue her true passion: playing bridge professionally. But she soon found that her card sense translated into a surprising skill for detection--and now she's making her bid to become the bridge world's first amateur sleuth ...

Cassie arrived seven minutes late for her lesson--and found her three students "late" in quite another sense. Someone had dealt Sonia Wetherhead a deadly blow, and Colonel and Mrs. Plumpton seemed to have expired of heart attacks on the spot. Now the stakes are raised, as another body is discovered...and Cassie must figure out which clues to discard--and how to trump a very tricky killer.