The son of a couple found stabbed to death at a house in south London has been arrested.
Police were called to reports of a disturbance at the maisonette in Croydon, London, on Wednesday afternoon.
The bodies of Barry Dighton and his wife Elizabeth, were found at the address. Both had suffered stab wounds.
Their 34-year-old son, Daniel, was arrested at the property. He remained in police custody when we went to press.
A Metropolitan Police spokesman said the victims were pronounced dead at the scene and a post-mortem examination would take place later.
Mr Dighton retired as headteacher of Elmhurst School, an independent boys' school in Croydon, about three years ago.
One neighbour whose son was taught there said the Dightons' son was working as a classroom assistant at the school until the end of last term.
Police have named another couple found dead in an unrelated incident.
Derek Rose and Jane Holden, both 44, were found at house in Skelmersdale, Lancashire, on Wednesday. A police spokesman said the pair suffered multiple injuries.
Police are treating their deaths as suspicious but are not looking for anyone else. Post-mortem examinations are being carried out.