A 14-year-old boy and 34-year-old woman have died following a house fire in south London on Saturday that also killed a five-year-old boy.
The teenager and woman were taken to hospital with serious injuries after the blaze in Russett Way, Lewisham, on Saturday.
The 14-year-old died from his injuries on Wednesday and the woman died in hospital a day later.
All three were members of the same family.
The five-year-old had died on Saturday and a post-mortem showed his death was caused by inhalation of fire fumes.
Detectives believe the fire was started deliberately but are not looking for anybody else in relation to the investigation.