A two-year-old girl who died when fire engulfed her bedroom may have been playing with matches.
West Sussex Fire and Rescue Service said today that was one of a number of possible causes to be investigated.
A spokesman said: "It is speculation at the moment but that is one of the possibilities."
Fire investigators were waiting to interview the girl's mother, who was recovering in hospital.
The 22-year-old suffered cuts to her hands, arms and legs after climbing through a broken window to escape the blaze which ravaged the ground-floor flat in Worthing on Saturday.
Neighbours tried to rescue her daughter, Libby Ann Louise Dor, but were forced back by heat and flames.
Her four-year-old son and a 17-year-old also escaped the blaze, which started in the Mendip Road flat at about 2pm.
All three were taken to Worthing Hospital suffering from the effects of smoke. The teenager was being transferred to East Grinstead for plastic surgery to his chest and arms.
The child is being cared for by relatives.
Firefighters arrived at the scene within four minutes of receiving the first of seven calls from anxious neighbours.
They found smoke billowing from the building and neighbours trying to tackle the flames and reach Libby.
The woman and youth had suffered severe cuts after climbing through double-glazed windows they had smashed to escape.
Sussex Police were last night trying to locate family members to inform them of the tragedy. It is believed the children's father lives in London.
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