UPDATE: Melissa Casias

The Melissa Casias case keeps unraveling, and the more we learn, the less anything makes sense. New details have emerged about the strange woman who showed up at Sierra's job to deliver $50 in graduation money, and the trail leads to a confusing tangle of mismatched names. Meanwhile, the family fracture has only widened, with a private investigator turning up the heat and the FBI now stepping in. Was Mark's theory about a subcontractor closer to the truth than anyone realized? Or is this just another dead end in a case that refuses to stay still?