San Antonio - A US official says the death toll from people found in the back of a sweltering tractor-trailer in the parking lot of a San Antonio Walmart has risen to 10.Thomas Homan, acting director of US Immigration and Customs Enforcement, told The Associated Press that two people died in a hospital. Eight bodies were found in the truck.Based on initial interviews with survivors, Homan says there may have been more than 100 people in the truck. Thirty-eight were found inside. The rest are believed to have fled or been picked up.Homan says some survivors have identified themselves as Mexican nationals. Police Chief William McManus says some of those in the truck ran into the woods, leading to a search. He says many of the truck's occupants appeared to be in their 20s and 30s, but that there were also what appeared to be two school-age children.Officials said the truck driver was arrested.The US Homeland Security Department is taking the lead in the investigation.