A schoolgirl suffocated to death inside a locked minivan in sweltering heat after the driver and teachers forgot to check.

Khemmanit Tongyoo, or Khemnit Thongyu, aged seven, had been travelling to school with her classmates inside the vehicle but she is believed to have nodded off by the time it arrived. The girl was left inside white minivan the other kids left to start classes in Chonburi province, eastern Thailand on Tuesday morning August 30.

Tragically, the driver did not count the number of pupils leaving the vehicle and her lifeless was found around eight hours later in the afternoon as the school staff prepared to take the children home after classes at 4 pm.

The girl, also known by her nickname Nong Jehun, was lying face down on the vehicle's floor with blood around her mouth. The was a black backpack and a glass of drinking water on the seat cushion.

Medics revived her at the Phanthong Hospital but she was later pronounced dead.

A school teacher who was the first to discover the little girl in the van said: ‘The van came and dropped all the students like normal. I went over and watched all the students come down. It looked like there was nobody left inside the van.

‘But then at 4 pm, the van was driven out to pick the students up after school. I opened the door and remembered feeling terrified when I saw the body of Nong Jehun lying on the van floor.

‘I touched her leg and she wasn't moving. I informed other people and we all came to know that Nong Jehun was no longer breathing.'

Khemmanit's mother Metika Kosonplangsri, 31, and father Thaianan Tongyoo, 28, broke down in tears when they were called by teachers. They arrived at the school and saw their daughter's body stretched across the floor of the can from where she had collapsed.

They both filed a report at Phan Thong Police Station as evidence against the school's negligence that had led to the death of their only daughter.

Metika said: ‘Three teachers came to my house - my daughter's class teacher, her mentor, and the van driver. They all looked stunned and only murmured questions about my daughter's congenital disease at me.'

‘At first, I thought my daughter might have been harassed or assaulted. But then when they told me Nong Jehun was no longer breathing, I was speechless.

‘I was shocked and I forced them to give me a valid explanation of what happened. My daughter is a second grader, she is not a toddler. I wonder how the teacher could not see my daughter inside the van.'

‘I'm afraid Nong Jehun's cause of death might be a lot worse than suffocation. What if somebody did something terrible to her and only made it look like she couldn't breathe to cover up.

‘I will fight for my daughter. I paid expensive school fees so she could go to a good school. I will find justice for my daughter's death. I only have one daughter and I raised her well.'

Police have already taken the schoolgirl's body to the hospital for a post-mortem examination to find the cause of death.

Police Major General Prasert Kulabutdee said: ‘We will be questioning the teachers that were related to the incident to follow legal procedures.

'The autopsy results will aid the investigation and CCTV cameras at the school will also be checked. If someone has been negligent they will be prosecuted.'