Heads You Lose by Christianna Brand

Grace Morland is a painter and she's been using that excuse to come and sit on Stephen Pendock's terrace at Pigeonsford Estate. Venetia Gold is a golden woman and she is mirrored by her twin Fran whose mien is rather darker. Grace is jealous of Fran who is young and vivacious and whom she assumes is after Mr. Pendock. When Fran gets a new hat, Pen shows his favor and Grace bites back that she wouldn't be caught dead in that hat. 

Well, it turns out that she IS found dead in that hat. Then, while the house guests are mour
ning Grace, another person is murdered. It's a twisty tale that is definitely a product of its time.

People familiar with Agatha Christie will probably figure out early who the killer is. I'm usually terrible and I figured it out. The problem is that Brand's sensibilities are jarring to read in a more enlightened time. Lots of sweeping generalizations that are racially based. 

Three stars
This book came out in 1941

Followed by Green for Danger

Borrowed as audiobook from Hoopla

Opinions are my own