Police investigating a fire which killed six members of the same family have said it could take weeks to find out the cause.
David Cuthbertson and five of his children aged between four and 12 died at their farmhouse in Llangammarch Wells, Powys, on 30 October.
Det Chief Insp Martin Slevin from Dyfed Powys Police said the fire remained "unexplained".
He said the fire's intensity had made it "difficult to identify the bodies".
Three children, aged between 10 and 13, escaped the fire and are being cared for by other family members and specially trained officers.
Mr Slevin said: "We want to get this absolutely right for the family and will do all we can to understand what happened here.
"It is likely to take several weeks, if not months, to conclude our work.
"While we are at the scene up to 40 people will be at the site at a time, and you will notice an increase of police cars and officers around the town.
"I would like to thank the local community for their support and patience so far while we investigate this tragedy, and hope that this continues as we move forward."
South Wales Police has joined the investigation, a press conference in the town was told.
Chief Supt Tony Brown, from the force, said an engineer had deemed the building "unsafe".
An operation to dismantle an estimated 260 tonnes of bricks and mortar was being conducted "brick by brick in order to preserve the evidence".
The bodies of Mr Cuthbertson and the other five children remain in the house which since has had scaffolding erected around the outside.
A temporary roof has also been put in place to "protect their dignity", according to Mr Slevin.
Mr Brown added that specialist forensic officers will enter the site once it has been made safe in order to recover the bodies, to identify them and then proceed to investigate the cause of the fire.