THE INVISIBLE ONES by Stef Penney

Gypsies add another layer of mystery to private investigator Ray Lovell's search for a missing woman.  Not only that, but Rose vanished about seven years ago.  When she married into the Janko clan, her family refrained from intruding into her new life, as is apparently the custom with gypsies.  As Ray gets to know the Jankos, especially handsome, taciturn Ivo, Rose's husband, he begins to suspect that Ivo murdered her.  Now Ivo is the sole caretaker of his beloved young son, Christo, who has the family disease—whatever that may be.  Several family members died young from this unknown affliction, but Ivo mysteriously and miraculously recovered.  Ray—still hung up on his soon-to-be-ex-wife—is half gypsy himself, although he was not raised as a Traveler.  When the book opens, Ray is in the hospital recovering from an exotic food poisoning that could have been accidental or attempted suicide or the result of foul play.  Ray's hallucinations and gnarled short-term memory make his illness just one more enigma that he needs to unfurl.  The first-person narration seesaws between the voices of Ray and JJ—a teenage member of the Janko family whose mother may be in love with Ivo.  I personally preferred the Ray chapters, where he sorted through and followed up on clues.  JJ's struggles are of a different nature.  He attends public school and, although he loves his family, has to grapple with the shame and ostracism that come with his offbeat lifestyle.  One of my many guesses about what was going on turned out to be right, but I certainly didn't come up with all the particulars.  If this book is not on your radar, it should be.