A police forensic team has confirmed that Friday's department store fire in Narathiwat province was caused by a bomb.
Narathiwat provincial police commander Pol Maj Gen Chote Chawalwiwat said bomb shrapnel was found and steel shelving was bent by the force of a powerful explosion.
Police believe the bomb was placed on shelving holding flammable products such as hair spray, leading to the quick spread of the blaze.
The authorities are examining surveillance camera images in an attempt to trace the bombers.
The fire started at about 10pm Friday in a back room of the one-storey Super Department Store on Chamroon Nara Road in Muang district.
The store is biggest in the province. The fire engulfed the store, razing it to the ground and spreading to houses nearby. The fire sent people fleeing in panic.
Provincial authorities had to ask water trucks from nearby districts and provinces. It was several hours before they managed to extinguish the blaze. Almost 95 per cent of the building was destroyed.
Super Department Store 4 Narathiwat deputy managing director Waraporn Sirichai said damage is estimated at about Bt100 million as the building and goods were totally destroyed.
More than 200 staff are now unemployed as it will take time to rebuild.
Waraporn said she wanted the government to help by extending compensation promptly as her business required capital to operate and time is needed to recover.
The company, which has been operating stores in the deep south since 2004, has been the victim of bomb and arson attacks on 17 occasions. This was the most serious to date.
“I almost dropped to my knees when my staffs called me to day that the store was on fire,” she said.