Something borrowed, someone dead - M. C Beaton

Incomer Gloria French is at first welcomed in the Cotswold village of Piddlebury. She seems like a do-gooder par excellence, raising funds for the church and caring for the elderly. But she has a bad habit of borrowing things and not giving them back, so when she is discovered dead, poisoned by a bottle of elderberry wine, folk in the village don't mourn her passing too intently.

Parish councillor Jerry Tarrant hires Agatha Raisin to track down the murderer. But the village is creepy and secretive and the residents don't seem to want Agatha to find who the murderer is, and Agatha's investigations are hampered by the emotional upset of finding her ex, James Lacey, has fallen in love with young detective Toni Gilmour.

And now the murderer is targeting Agatha!