A four-year-old boy in central China has died after being accidentally locked inside an unofficial school bus, local media has reported. The driver had not realised the boy, nicknamed Tian Tian, was still inside the seven-seat people carrier, which was used as an unofficial school bus, and he was trapped inside for several hours in temperatures that topped 30 degrees Celsius (86 Fahrenheit). Police in Wuhan, Hubei province, have detained the head teacher at the unlicensed kindergarten and her husband, who acted as a part-time driver, Knews.com reported on Sunday. Chinese man held over attempt to steal baby from hospital The boy’s mother Wu Xuemei said she sent the boy off to school in the vehicle at 7.20am, adding that the kindergarten had got in touch at 4pm to tell her the boy had died. “My child took this school bus to school every day and the driver works for the kindergarten,” the woman said. “There is no label that shows the vehicle is a school bus. It’s just the driver’s private vehicle.” The driver told police that he had driven a total of eight children to the kindergarten that morning and two teachers picked them up before taking them into the classroom, the report said. Neither the driver nor the teachers noticed that the boy was still inside the car. Kidnap victim escapes from car boot after crash The driver then drove the vehicle to his full-time workplace and parked it out in the open. His wife came to pick up the vehicle at around 3pm to drive her pupils back home and found the boy was unconscious. Doctors were unable to save him and concluded he had died of suffocation. The case is still under investigation by police.