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.
Police said the fire had not been started deliberately.
Det Sup Fiona McCormack said she wanted to hear about anyone who was in the tower, whether or not they were meant to be in the building.
She said: “I do not want there to be any victims of this tragedy that we do not know about.
“Our priority is to understand who was in Grenfell Tower. We are not interested in people’s reasons for being in Grenfell Tower.”
The fridge freezer the fire started in was a Hotpoint FF175BP model. Police say the manufacturers have been told, as well as the Department of Business Energy and Industrial Policy.
Further tests were being done on the appliance, they said, and the fridge freezer had never been subject to a product recall.