Police will consider manslaughter charges as part of the investigation into the Grenfell Tower blaze, which left at least 79 people dead.
Scotland Yard said on Friday that the fire started in a faulty fridge and that insulation and tiles on the block failed safety tests.
The Government has ordered an immediate examination by experts of the model of Hotpoint fridge freezer involved in the fire.
Nine out of the 79 dead or presumed dead have been formally identified, police said.
Metropolitan Police Detective Superintendent Fiona McCormack said: “I know there is a fear that that number is a lot higher and I do not want any hidden victims of this tragedy.”
Police said they are still trying to establish who was in the 24-storey tower block the night the fire broke out last Wednesday.
DSI McCormack confirmed that neither the police, nor the Home Office, will use the tragedy to check the immigration status of anybody in the block and urged friends and relatives of those feared missing to come forward.
The search of the Lancaster West Estate high-rise could take until the end of the year.
Police said there are currently more than 250 specialist investigators working on “all aspects” of the investigation.
“The terrible reality is we may not find or identify all those who died in the fire,” DSI McCormack added.
“I fear that there are more. I do not know who they are at the moment, which is why I am pleading for the public to call us on this.”
Documents have been seized, police said, but they have not carried out any raids of businesses.
The announcement that police are considering manslaughter charges comes after Labour MP for Tottenham David Lammy said that the local failings at Grenfell should not be “brushed under the carpet”.