Whiskers in the Dark: A Mrs. Murphy Mystery by Rita Mae Brown

Harry is working with the National Beagle Club at Aldie as the date for its springtime Hounds for Heroes veterans’ benefit approaches. Susan, her best friend, is there, too.  While they are chatting about an old murder just found, they discover a brand new murder right at the club.  His throat has been cut from ear to ear.  He's a rich man who's very nice, who would kill him?  What's worse is its must have been someone at the club...

Bantam Books and Net Galley let me read this book for review (Thank you).  It will be published June 4th.

The dead man's wife comes to the show with their dogs.  He was going to show them so she'll be doing it in his memory.  After the show she heads back for her cabin.  They find her in the horse barn, dead.  It looks like natural causes,  but she was poisoned.  The mystery deepens...

These deaths are related to spy activities during the war.  Harry eventually puts that together.  However she doesn't realize how close to death she herself is...