In the Mexican State of Sonora, which borders the U.S., hundreds of people are reported missing and believed to be victims of violence between rival crime factions. Reporter Ruben Pereida joined a group called the "Caborca Trackers" who go on a grim quest to find missing victims. Veronica Villafañe narrates the story. First a caution — this report contains graphic images and viewer discretion is advised. Videographer: Ruben Pereida; Video Editor: Veronica Villafañe