Kedah police chief Fisol Salleh said they suspected that petrol was used in the incident after finding a mineral water bottle half-filled with the fuel at the scene, Berita Harian reported.

Police later found that the elderly victim had lodged a police report a day before the incident that his nephew had stolen his handphone.

“The report was retracted not long after that, before the fire occurred,” Fisol was quoted as saying.

Five people were arrested yesterday, with the elderly victim’s nephew the main suspect. The motive is believed to be revenge.

Fisol said three of the suspects were believed to have been directly involved in the blaze.

He said the suspects, aged 19 to 53, included a Myanmar man who was living in the house. Three of them have criminal records, including for narcotics offences.

“Three of the five suspects tested positive for methamphetamine,” Fisol was quoted as saying.