Two people are dead and 10 others hospitalized after an unknown medical emergency on board a freight train in Uvalde County, Texas, on Friday. The incident is being investigated as a suspected human smuggling operation, and Union Pacific, the railway company operating the train, said four of the 10 hospitalized patients were flown to facilities in San Antonio. The cause of the medical emergency is still unknown, and the incident has raised concerns about the safety of migrants attempting to cross the U.S.-Mexico border.