Claws for Alarm (A Nick and Nora Mystery)

Sandwich shop owner Nora Charles continues her quest to find her cat Nick's previous owner. But her investigation is put on hold when her sister, Lacey, is arrested for murder. The victim, an esteemed art collector and Lacey's bullying professor, was stabbed in the heart. Apparently, all over a lousy grade. Luckily Nora still has a few sleuthing tricks up her sleeve. And Nick, whose previous owner was a Private Investigator, knows a thing or two about crime as well (he's a dab paw at spelling out clues with scrabble letters).