A woman has been arrested on suspicion of murder after three children were found dead at a house in London.
Officers discovered the bodies after being called to the property in New Malden, south London, at around 9.30pm yesterday.
A Metropolitan Police spokesman said: "A 42-year-old woman has been arrested on suspicion of murder and remains in custody.
"We are not looking for anyone else in connection with this incident."
The children's father, Gary Clarence, was not at home at the time of the deaths.
In a statement Mr Clarence's employer, City bank Investec, said: "We are doing all that we can to help Gary and his eldest child and ask that their privacy is respected."
A neighbour said the family, originally from South Africa, were "really, really lovely people".
She said they moved into the large semi-detached house in Thetford Road with their four children a year ago.
She said the three younger children, four-year-old twin boys and an older girl, were suffering from genetic disorders, believed to be life-limiting.
However, the eldest child, thought to be around seven or eight years old, was in good health.
She said the father works in the city and that the mother is a full-time carer for her children.
Neighbours said the family moved into the house after it underwent a "massive" refurbishment, including the installation of a lift.
"They are very nice people and very, very decent. She is such a lovely person, her life revolves around the children," one woman said.
She said the family have a nanny and help from carers.
The woman is being held for questioning in a south London police station.
Crime officers were earlier seen leaving the property carrying evidence bags.