All six people whose remains were discovered in a boxcar in South Texas died from heatstroke before they were found by law enforcement, Laredo Mayor Victor Treviño said at a news conference Thursday. The victims were previously identified as five males and one female, ranging in age from 14 to 56, according to the Webb County Medical Examiner’s Office. Authorities have not released their names. Three of the people were from Mexico and three were from Honduras, police said. “Today, our community is still mourning a heartbreaking discovery,” Treviño told reporters. “Let me be clear, we are demanding justice for these lives lost,” he added. “It doesn’t matter where they came from.” Laredo Police Chief Miguel Rodriguez at a news conference Thursday about the discovery of six dead people in a boxcar.…