Four family members died early Saturday in a blaze at a four-storey commercial building in Muang district of Suphan Buri province.
The fire at the building on Nang Pim Road was reported to the police around 5am. Fire engines and crews from the Muang Suphan Buri Municipality took about two hours to control the flames.
The building stored highly flammable materials such as hardware, construction materials, electrical equipment and paint, making it difficult for firefighters to extinguish the blaze.
Police identified the building's owner as Pusit Rungrojchaiyaporn, a former district council member and a candidate for a local administrative organisation.
Ekaphan Injai-euar, mayor of the Muang Suphan Buri Municipality, said that as firefighters controlled the flames and entered the building, they found three bodies trapped on the third floor and another in the stairwell of the second floor.
The victims were identified as Pusit, 52; his wife Kanokwan, 49; their son Tewarat, 26; and their daughter Warasiri, 24.
Police were investigating the cause of the incident and said it was believed the family could not escape in time after the fire broke out.