RIO GRANDE VALLEY - The brutal temperatures of South Texas are on the decline, but the danger faced by immigrants attempting to illegally enter United States are not. Over the past three days. US Border Patrol agents from the Rio Grande Valley sector saved the lives of four people and found the decomposing remains of four others. Extreme heat, combined with rugged terrain, can rapidly cause an individual to become distressed and die from dehydration or another heat-related illness. So far in 2012, agents have saved the lives of more than 310 people and found the remains of nearly 150.