Jean Guerrero: Unending deaths of migrants, driven by desperation and US border policies

It's one of the deadliest mass-casualty events connected to border militarization in years. The number of migrants found dead in a tractor-trailer in San Antonio Monday rose to more than 50 on Tuesday. Another 16 people, including four children, were transported to hospitals with heat-related illnesses.

Across Latin America, the terrified parents, children and siblings of people who recently crossed the border are desperately trying to learn whether their loved ones are among the dead. Calls have been pouring into search and rescue groups such as . This trying to enter the U.S. in 2009.