Australian twin girls Aisha and Lailani huddled together holding hands as they were killed in a ferocious house with their mother was locked outside.
Their mother Tanyka Ford, 29, had spotted the three-year-olds playing with a burning pillow beside a log fire when she snatched it from the girls and took it outside.
The twins playfully locked the door behind their mother.
Within four minutes flames soared four-metres high, engulfing the house as the Mom and neighbors desperately tried to force their way inside the home.
Police said the Mom and her and five-year-old son Dominic could do nothing but watch from the footpath.
The sisters, who are believed to have died from smoke inhalation, were found unconscious and holding hands in the front room.
Riverina Police District Commander Bob Noble said Strike Force Edmondson would be investigating the tragedy and police had an 'open mind' about how it unfolded.