The fire happened around 3:00 Saturday morning on the 1400 block of Sterigere Street in West Norriton, Montgomery County.
"I knew the house was gone. It was ruined," said Raymond Knauer, neighbor.
Flames ripped through the home and heavy smoke took over. Bridgeport police officer Jerry Cunnane was passing by and jumped into action.
Neighbors say 53-year-old man Nicholas Cavello, who lived in the home, made it out safely.
He went back to save his 90-year-old mother - Vera Cavello, who was trapped inside.
"He tried to go back into the house but the door was locked and a police officer pushed it in and when they pushed it in the flames shot up," said Knauer.
When Norristown firefighters reached the scene, they went to work attacking the fast moving fire but the conditions were intense.
They finally reached the woman. Neighbors say she is well known in the community because she's lived there for most of her life.
The elderly woman suffered severe burns and was in cardiac arrest but paramedics with Plymouth Ambulance revived her and rushed her to the hospital.
Nicholas also suffered smoke inhalation and other injuries.
Both victims are listed in critical condition at Temple University Hospital.
A cause for the fire is still under investigation.