A joint investigation between London Fire Brigade and the Metropolitan Police has been launched following a fatal fire that took place in Tooting.
Police fire and paramedics were all scrambled to Fountain Road just after 11pm on Wednesday evening.
A blaze has ripped through the Terrace property trapping at those involved near to St Georges hospital.
Local residents spotted smoke and flames issuing from the building and alerted the Fire service.
One upset man said he helped the family move in less than a week ago said that he was beaten back by the smoke and could not gain access to the property and had to wait for the fire service. A woman was found dead on the ground floor of the property.
But from speaking to residents it is understood other people have been hurt. Curtains on the first floor can be seen burnt away.
Specialist FIT investigators from the London Fire Brigade have been working through the night with scenes of crime officers from the Metropolitan Police in an attempt to establish the cause of the fire.
It is understood that the incident is being treated as arson.
A crime scene has been established around the property.
A Spokesman for the Met Police said: Police were called by London Fire Brigade at approximately 11.15pm on Wednesday, 7 July to reports of a fire at a residential address in Fountain Road, SW17.
The body of a woman, believed aged in her 40s, was found deceased inside the address.
Next of kin have been informed.
While the cause of the fire remains under investigation, at this early stage police are not treating the incident as suspicious.
Enquiries are ongoing.