The Grenfell Tower fire in London started in a fridge freezer, and outside cladding failed safety tests, police say.
Insulation on the building also failed tests and the Metropolitan Police will consider manslaughter charges.
Seventy-nine people are feared dead after the blaze destroyed 151 homes in the Kensington tower block.
The government has ordered immediate testing of the Hotpoint fridge freezer which was involved.
Whirlpool, who owns Hotpoint, said: “We offer our most profound condolences to the victims, those who have lost loved ones, homes, and possessions, and to their friends and families.”
Nine of those who died in the 14 June have been formally identified so far. Nine people remain in hospital, with three people still in critical care.
Police said the fire had not been started deliberately and the speed with which the fire spread was “unexpected”.
Preliminary tests on the samples of insulation showed it burned soon after the test started, and more quickly than the cladding tiles.
However, they both failed the police’s safety tests – which are similar to those being carried out by the UK government.