Looking for a mystery novel about an art theft with a lesbian plot twist

Hi, I’m trying to find a novel I read more than 10 years ago. I bought it in Venezuela (at Librería del Sur). I don’t remember the title or author, but here’s what I recall:

• The story revolves around the theft of an expensive painting or piece of art, possibly from a museum.
• There is a detective or police investigator involved in the case (he might be the protagonist).
• A woman becomes romantically involved with him. He falls for her.
• Plot twist: in the end, it is revealed that she is in a relationship with another woman (she is lesbian or bisexual).
• The book was more focused on the crime/mystery than on the romance.
• The cover was pink.
• I remember the words “series” and “art” being on the cover (not sure if they were part of the title or a collection name).
• I think the author had a Greek name or was of Greek descent. The name was difficult to remember.

It was not a very mainstream bestseller (at least not that I’m aware of).

If this sounds familiar to anyone, I would really appreciate any suggestions. I’ve been looking for this book for years.