A murder investigation was launched today following the death of a 15-year-old girl who was seriously injured in a fire at her home.
Maleha Masud died in hospital at 9pm last night, following the suspected arson attack on her family home in Tooting, south London, last Sunday morning.
Three of her siblings were also injured in the blaze in Lessingham Avenue and remain in a critical condition.
Her mother, Rubina Masud, 53, who was discharged from hospital, said: "I am devastated at what's happened. I can't believe anyone would do such a thing.
"I am just really concerned for my children. Please pray for them."
City banker Zain Masud, 22, and his mother jumped from a first-floor window to escape the blaze.
His three siblings, including Maleha, were dragged from the burning building by paramedics.
Nabiha, 21, had to be resuscitated by paramedics in the front garden.
She and Mr Masud, their younger brother Junaid, 16, and Maleha were taken to hospital for treatment for burns and smoke inhalation.
The Metropolitan Police confirmed the blaze was being treated as suspicious and said they had found traces of an accelerant.
Two boys, aged 14 and 15, were arrested in connection with the fire and bailed until August, pending further inquiries. No charges have yet been brought.
Detective Chief Inspector Damian Allain, who is leading the investigation, said: "A mother has had her youngest child taken from her in the most tragic circumstances.
"Her three other children remain seriously ill in hospital. They were at the place where they should feel safest, in their family home.
"Whoever has committed this act is not only a coward but is a dangerous individual who must be caught."
Police are keeping an open mind as to the motive and appealed for people to come forward with information.
He asked members of the public to consider whether they were in the area between 4am and 4.30am last Sunday, the day of the London to Brighton cycle race.
Anyone with information which might help the inquiry should call the incident room at Lewisham on 020 8721 4805 or Crimestoppers, anonymously, on 0800 555 111.