Police have begun a detailed search of the former home of a paedophile after a tip-off that human remains were buried in the garden.
A "fingertip" search of the garden has begun
Officers combed the garden on their hands and knees and searched the house in Walton Green, Croydon, south London.
It follows an investigation into a letter which claimed bodies were buried 35 years ago.
Leslie Ford-Thrussell, 72, lived there for 17 years, until he was jailed for sex crimes against children in 2004.
He was not the tenant at the time of the alleged events and has not been interviewed about the investigation.
Police are investigating whether he had any links with the property before he moved in.
They have refused to confirm newspaper reports about who sent the letter, saying simply that it was anonymous.
But they have said they have identified and spoken to the writer, who sent the letter 12 months ago.
Det Insp Mark Stockford said the delay was necessary to establish the facts, and has said they are not even certain a crime has been committed.
Police have been trying to reassure neighbours
Ford-Thrussell is currently serving a 12-year jail term for sex crimes committed against children, aged 13 and under, from 1986 to 2003.
Among the offences were rape, indecent assault, gross indecency with a child and taking and making obscene images.
The search at the council-owned property on the New Addington estate will involve forensic archaeologists and specialist equipment to survey the plot.
Officers are then expected to excavate the back garden which is part-paving, part-lawn.
The unsigned letter was sent to former residents of the house who are not connected to the investigation.
The house has been empty since the last tenants moved out about three months ago.
Officers delivered leaflets to local people on Tuesday informing them the operation may take several days, offering reassurance.
They have also reviewed missing person files from 35 years ago, the time of events mentioned in the letter.
The search has finished for the night and will resume on Thursday.