Police are appealing for information and witnesses after a block of flats in Brixton was set alight earlier this month. The fire is being treated as suspicious.
Smoke from the blaze at Chartham Court, Canterbury Crescent, could be seen across London.
Three people were treated for the effects of smoke inhalation by the ambulance service and two were taken to hospital. Both have since been discharged.
Police believe the fire started in a shed belonging to a ground-floor flat. It quickly spread throughout the block causing significant damage.
Although the fire started shortly after 1pm on Saturday 11 June, detectives are keen to hear from anyone who may have seen a woman near the flats from around 11am.
She is described as a white woman, aged 30 to 35, 5ft 5ins tall, of medium build with long brown curly hair. She was wearing a red top and black leggings.
She was seen between 11am and 12:22pm. Detectives from Lambeth CID are trying to establish where she was and what she was doing between the last sighting and when the fire started.
DS Dick Nation said: “It is very fortunate that no one was seriously injured, given the extent of the fire. The outcome could have been significantly worse had the alarm not have been raised so promptly.
“Due to the actions of the person or people responsible a number of the residents are still unable to get back into the properties and a small number of the flats have sustained significant damage.
“I am keen to hear from anyone who may have seen or heard anything prior to the blaze being started. Any information no matter how small may be vital in helping us progress this case.”
Anyone with any information is asked to call Lambeth CID on 020 8649 2152 or Crimestoppers anonymously on 0800 555 111.
On Saturday 11 June 2016, a 34-year-old woman was arrested on suspicion of arson. She has been bailed to a date in mid-September.