The Lifeline by Margaret Mayhew

Ruth has taken over her dead mother's manor and grows plants for sale there.  Her husband is the local doctor and he refers patients to her to work on easy tasks in the garden and help them get their minds straight again.

Severn House and Net Galley let me read this book for review (thank you).  It will be published on June 2nd.

The gardening project is going along well until they find a dead body in the tomato plants...

Laurence was recovering from a stroke and was not a very nice man.  He said nasty things to everyone, so there are plenty of suspects.  They ask the Colonel to investigate because the cops have picked the local mentally challenged young man as the killer.  No one but the cops believe that.

The Colonel questions everyone and finds no suspects.  Then he remembers what one witness said he saw.  He goes to ask one person some new questions...