"It was getting dark when I got the call. Luz, my wife, was telling me that they had killed her brother Beto. She was uncontrollable — I had never heard her speak like that. Her voice was shaking, breaking. I could not sleep all night. "Beto was killed, hanged," resonated in my head, "he was beaten, burned, but they told us that he committed suicide.” Her other brothers, David and Nacho, had been missing for over 3 months. 

After these events in 2013, I began to document my family and the families of other missing people in Mexico, where the government has categorized more than 37,400 people as...