A teenage boy found suffering burns has been charged with arson after a suburban home went up in flames.
Fire destroyed the home in Abbotsford, in Sydney's Inner West, about 4am on Tuesday, before officers arrested the 17-year-old nearly 20 hours later.
Three occupants were treated for smoke inhalation, and an 88-year-old woman was rescued from a balcony by police officers and a brave civilian.
Investigators quickly deemed the fire suspicious, with a neighbour seeing a male in a balaclava allegedly spreading accelerant before the blaze.
About 11pm, detectives descended on a home in Merrylands, near Parramatta, and arrested the 17-year-old.
He was treated for burns to his hands and legs and taken to a hospital in a stable condition.
The teen remained in the hospital on Wednesday morning and was set to face bail court later in the day.
He was charged with arson, joy riding and property fraud.
Detectives from a police squad investigating youth crime networks and arson investigators executed a search warrant at the Merrylands home, seizing several items of interest.
Addressing reporters on Tuesday, Superintendent Christine McDonald said the Abbotsford home's occupants were not believed to be criminally linked.
She commended the "one very brave civilian" who helped rescue the 88-year-old woman from the burning building with a ladder.
"I've just seen the body-worn footage of that particular rescue, and can I say I am incredibly proud of the police and the 49-year-old civilian who rescued that woman, they saved her life," she said at the time.
The superintendent also said a neighbour confronted the suspect, initially described solely as a man in a balaclava, as he fled to a red Holden getaway car.
The two-storey Weddle Avenue home was destroyed by the time the fire was fully extinguished on Tuesday.
Entire sections of walls and the roof were missing as burnt debris could be seen piled up on the lower levels.
Fire and Rescue Acting Superintendent Peter Murray said about 40 crews and 10 trucks were in attendance at the height of the incident.
The blaze at one point spread to an adjoining house, though authorities were able to contain it within the building.
