Historical detective novel with a transgender character?

We've gotten a real stumper at our Reference desk. Description provided by patron:

• Historical fiction murder mystery
• possibly 18th century
• noble woman who was murdered
• It was discovered that she was a transgender or transsexual or intersexed. (Our patron can't remember which.)
• There was a male detective as the protagonist
• The manor house was having construction work done
• The murder victim was originally from South America or the Island
• It is not a new book. - she read it 2 or 3 years ago (but it may not have been new at that time)
It is not:
Lady Adley's Secret.
The Twelfth Night Murder by Chuck Palahniuk
A short story
Any of the books on www.historicalnovels.info/eighteen-century.html

NoveList didn't have anything. I've been scouring LGBT booklists on GoodReads and haven't come up with anything. :(

Misfortune by Wesley Stace? It's been a long time and I can't remember the plot very well

Misfortune isn't a murder mystery.

Found it: A Dark Anatomy. Reviews mention the victim is a "hermaphrodite."

GREAT! Thank you so much. We've got an email out to our patron pointing her to A Dark Anatomy. :)

Side note: the reviews for this book were all over the place.