A candle has been burning for almost a year in the modest front room of the tiny two-bedroom apartment that Guadalupe Reyes shares with her husband, Bernardo, and their 10-year-old daughter, Tania.
Next to the candle is a picture of their older daughter, Mariana. Her 19th birthday was this month, but the family hasn't seen her since she left their house in a working-class area of the Tecamac municipality, in the state of Mexico, nearly a year ago. She went that day, Sept. 17, to a photocopy shop no more than a 10-minute walk away. After she had been gone an hour, her parents launched a frantic search that continues to this day.