The root cause was suspected that the 6 years old child was playing with lighter upstair while his granny was doing house chore downstair. Accidently the fire started to spread. The granny was only notice when someone opposite shout that their house caught fire. The granny immediately escape out from the house with her grandchild.
She knocked on my door to borrow the phone but my sis thought it was just some swindle and do not bother her. Later only she sense something went wrong because it was a bit chaotic outside and some burning smell.
My house was lucky to escape being affected because my neighbour had build up a high wall as a divider and that wall had blocked the fire from spreading over.