Six people who were found dead in a rail yard shipping container in Laredo, Texas, were from Honduras and Mexico and included a 14-year-old boy, all part of a human smuggling effort, authorities said Thursday. Police released more details about the discovery made Sunday in Laredo, near the U.S. border with Mexico, but said federal authorities were leading the investigation. “They did not pass away in our city, but they were discovered here after hours of suffering,” Laredo Mayor Victor Treviño said at a news conference. “We are demanding justice for these lives lost. It doesn’t matter where they came from.” The bodies were discovered by a Union Pacific employee. The Webb County medical examiner suspects the deaths were caused by hyperthermia, or heat stroke, a conclusion repeated by the mayor. The six people were put in the shipping container on Saturday in Del Rio, Texas, two days after the train departed from Long Beach, California, Laredo Police Chief Miguel Rodriguez Jr. said.…