Manslaughter charges are being considered by detectives investigating the Grenfell Tower fire as it emerged the structure had failed fire safety tests.
Metropolitan Police Detective Superintendent Fiona McCormack said a faulty fridge-freezer started the inferno, which has killed at least 79 people.
Cladding and insulation encasing the building did not pass any fire safety tests, she added, increasing concern the 24-storey block’s facade accelerated the blaze’s spread.
The revelation comes as a nationwide hunt for high-rise buildings with flammable cladding continues, with thousands of people finding their homes were potentially dangerous
By Friday afternoon, the Government said 14 buildings across nine local authority areas in England were found to have flammable cladding.
As police continued to unpick the roots of the disaster, Ms McCormack said a string of criminal offences were now being considered.
Documents and materials had been seized from a "number of organisations", she added.
She said: "We are looking at every criminal offence from manslaughter onwards. We are looking at every health and safety and fire safety offences and we are reviewing every company at the moment involved in the building and refurbishment of Grenfell Tower."
A Hotpoint FF175BP model was found to have been the fridge-freezer at the centre of the tragedy and followed witness reports from June 14 that one resident claimed his appliance was responsible.
Tests on the building’s material as part of the police investigation were "small scale", the officer said, but added: "All I can say at the moment is they (tiles and insulation) don’t pass any safety tests.
"What we are being told at the moment by the Building Research Establishment is that the cladding and insulation failed all safety tests."
Towers in Camden, Manchester, Hounslow and Plymouth are among the at-risk buildings, the Department for Communities and Local Government said.
Hundreds of further buildings are being tested by the Government to see if they pose a fire threat.
While the death toll remains at 79, Ms McCormack addressed concerns that many more had died and were unaccounted for in official figures.
She repeated calls for members of the public with information about people who may have been in the tower at the time of the fire to come forward.
An amnesty for people who may have been living in the tower illegally has been suggested, supported by Mayor of London Sadiq Khan.
Ms McCormack said: "Every complete body has been removed from the building.
"I remain really concerned though that we do not have a complete picture.
"There may well be people who no one has contacted us about - who they know were in the building or have close links to Grenfell Tower.
"We are not interested in people’s reasons for not telling us sooner and as the mayor has already said, people should be not be nervous about contacting us.
"The Home Office has assured us that they are not interested in people’s immigration status and we are not interested in looking at that.
"What we are interested in is making sure that we know who is missing and we take every possible step to establish if they are safe and well."
Describing how the investigation was proceeding, she added: "We have been in Grenfell Tower, from top to bottom, last week.
"Next week, we will be installing a lift to the outside of the building to assist. But our forensic search may not be complete until the end of the year."
Downing Street said the testing facility being used to check council and housing association tower blocks was also available to the owners of private blocks who were being encouraged to use it.
A Number 10 spokeswoman said: "DCLG have spoken to local authorities about private sector residential blocks. The testing facility is available to them. We expect many of them to use it.
"We are encouraging local authorities right now to make sure that private landlords are made aware that is what we want them to do."
The spokeswoman indicated that the Government was ready to step in if they failed to do so.
"We will probably have to ascertain later today if that is happening what the next steps might be," she said.
A total of 151 homes were destroyed in the blaze, including 129 in the tower itself and 22 from nearby Grenfell Walk, the Royal Borough of Kensington and Chelsea said.
A council spokesman said: "363 households have been placed in hotel accommodation in or as near to the Royal Borough as possible, 213 households of which are from the cordon area which surrounds the Tower and Walk.
"No one has been housed outside London, Royal Borough officers are working with families to identify suitable accommodation so they can move as quickly as possible from hotels."
Labour leader Jeremy Corbyn said the police "must be allowed to make that judgment and make that consideration" of corporate manslaughter, given the tragedy could have been prevented.
He added: "If there is a death as a result of negligence by a company or by the public or by the administration, then there is a process of corporate manslaughter."