The Butterfly Clues by Kate Ellison
Penelope "Lo" Main has always loved to collect beautiful things.
But in the year since he brother's death, Lo's hoarding has blossomed into a full-blown, potentially dangerous obsession. When she discovers a beautiful antique butterfly figurine and recognizes it as having been stolen from the home of a recently murdered girl known as Sapphire, Lo becomes fixated.
As she attempts to piece together the mysterious "butterfly clues", with the unlikely help of a street artist named Flynt, Lo quickly finds herself caught up in a seedy, violent underworld--a world much close to home than she ever imagined.