Inspired by a story about a missing border crosser that he heard on NPR over 4 years ago, New York-based filmmaker and New York University professor Marco Williams went on a journey.

It led Williams to both Arizona and Mexico, where he spent months filming alongside the U.S. Border Patrol, the Pima County Medical Examiner's Office. He also spent time with the families of men and women who left their homes in Mexico in hopes of illegally.crossing the border. Some of them were never heard from again.

Williams says that his goal for The Undocumented is to put a human face on the story of thousands of migrants who have perished between Sonora, Mexico and Tucson.

The series Independent Lens presents The Undocumented on PBS 6 on Monday, April 29th, 2013 at 10 pm.