A laundry shop owner from Phitsanulok was found dead inside his car in a park in Sukhothai on Wednesday evening.
The body of Watanasak Yanmook, 45, from Phitsanulok's Muang district, was found dead in the driver's seat by officials from King Rama IX Park in Sukhothai's Muang district.
He had placed a stove on the floor in front of the back seat and it was still alight with charcoal and emitting fumes.
Park officials said they had seen the car parked at the same spot at 4pm while it was raining heavily. When the park was about to close at 8pm, the car was still there so officials went over and checked it.
A suicide note had been attached to the window behind the driver's seat, asking anyone who found the car to contact a teacher in Sukhothai with a phone number provided. The note said the teacher would later return all the belongings to Watanasak's wife, No-on Yanmook, in Phitsanulok.
A doctor determined that the man suffocated about three hours before he was found.