Detectives were investigating today whether a man found dead after a massive explosion ripped through four homes was murdered.
Officers believe the blast may have been sparked deliberately leaving two other people suffering serious injuries.
Shocked neighbours spoke today of how they dug through smoking rubble with their bare hands after a huge bang shook their homes.
The explosion demolished three terraced properties in Stanley Road, south Harrow, north-west London at about 9.30pm last night.
Gravedigger Andrew Haynes, 44, said it took at least 15 minutes to pull a 17-year-old girl from one property that had been split into two flats.
He said: "There was a girl's arm just poking through the rubble and there was a beam on her. It looked like the ceiling had fallen on her and she was entombed in there.
"It took us about 15 minutes to get to her. I kept telling her she was going to be OK. She was covered in dust, she had lacerations on her stomach and was in a pretty bad way."
Emergency services were working to make the remains of the properties safe today before removing the body of the dead man.
Firefighters rescued two other people from the rubble and initially feared others may also be trapped.
A 26-year-old man suffering from serious head injuries was taken to Northwick Park hospital in north-west London.
The 17-year-old girl, named locally as Charlotte, was taken to Chelsea and Westminster hospital with severe burns.
A Scotland Yard spokesman said the cause of the explosion had "yet to be established".
Detectives from the Specialist Crime Directorate, responsible for the capital's most serious criminal cases, are investigating.
Neighbour Paul Redmond, 42, whose front door was blown off, said when he left his house people were already searching for survivors.
He said: "I was terrified. I feared for my life.
"I was just putting the kids to bed. The wife was at a meeting - thank God she was out of the house."
"I've never heard a bang like it. I did not know what it was the kids came running in to me screaming.
"I threw some clothes on them and we ran straight downstairs. Bits of rubble were still falling off next door and people were in the street searching for survivors."
Mike Leahy, 42, who lives in one of the damaged properties, survived because he was at his ex-wife's house watching television. His lodger was saved by Tube delays.
"If it wasn't for The Apprentice, I would have been caught up in it," he said. "Usually I'm in at that time. I'm lucky to be alive."
Artist Dan Llywelyn Hall, 27, and his girlfriend Aurelie Derjuesse, 29, live opposite the blast site.
He said: "I've heard reports of gas leaks from other people but I've never smelt anything myself."
Miss Derjuesse, a teacher, said: "I didn't know what it was at first. You automatically think it's a bomb but it soon became clear that it wasn't.
"It was a horrible experience. The smoke was very choking and it was all quite panicky for a time."
National Grid said the pipes leading to the house had been checked and the supply isolated overnight.
"We found no trace of a gas leak in our system but we will continue to have a very small presence on site," she said.
Inspectors from the Health and Safety Executive arrived at the scene today.
Harrow Council said 40 people were evacuated and taken to a nearby Royal British Legion building.
The site is less than a mile from Drinkwater Road where a gas explosion demolished a top-floor flat in February.
* Residents affected by the blast should call Harrow Council on 020 8736 6000.