Luis Alberto Urrea wrote The Devil's Highway as a kind of expose of the kinds of horrors which routinely happen at the Mexican-American border. Specifically he follows a group of men called the Wellton 26. Fourteen of them, known as the Yuma 14, did not survive the crossing.
On the last page of the book, a secretary in the Yuma coroner's office discovers that the death certificates of the fourteen Mexican men who died in the crossing all say they were "white males." Once she makes the discovery, the "files go on a shelf; a stack of newer files is dislodged and falls over." The woman leaves and these men, Urrea implies, will be forgotten, lost amid many more deaths.
Urrea is a researcher, and he does not state any reason why the death certificates were incorrect; however, readers can draw a few conclusions about what the fact means. First, no one cares enough to get it right, even in a case which rose to international prominence. Second, these fourteen men were treated as carelessly in death as they were in life (and not just in America). Third, in death these men have been betrayed again by people who should have cared more about what happened to them.
Why it happened is unknown; the fact that it happened and was not corrected is the tragedy.