A chilling letter thought to have been sent by the notorious serial killer Jack the Ripper to Ealing Police in 1888 has been sold at auction for £22,000.
The letter, in which the Ripper boasts his "knife is still in good order", had been kept in police files on the gruesome mass murderer until the case was closed.
It was auctioned off on Monday (April 30) and rocketed past its £600 to £900 estimate.
It is believed the Ripper sent the postcard, which warns of two more murders, to Ealing Police Station on October 29, 1888, which would be just 11 days before the serial killer's last suspected victim Mary Kelly was disembowelled.
Mary was the last member of the Canonical Five, who most experts agree are likely to have been victims of the notorious Victorian serial killer.
Jack the Ripper is famous for having typically killed prostitutes in and around Whitechapel, which in Victorian times contained the slums of London.
He was also known at the time as the Whitechapel Murderer and often sent letters to newspapers and Scotland Yard .
The letter warns: "'Beware there is two women I want here they are b*******, and I mean to have them my knife is still in good order it is a students knife and I hope you liked the kidney. I am Jack the Ripper.''
The postcard was bought by a private British collector, who was embroiled in a bidding war with an American collector.
The new owner will end up paying around £30,000 for the letter, factoring in the auction premium.
The letter had belonged to an Ealing police constable, who received the letter as a memento on his retirement in 1966.
He had kept it in a drawer until his death, when ownership passed down to his widow.
Jonathan Riley, of Grand Auctions Ltd, in Folkestone, Kent, said: "He happened to be in the right place at the right time, he was retiring, and took it and stuck it in a drawer for 30-odd years. I'm incredibly happy (with the sale) and so is the vendor (to have bought it)."
Before the auction, the auctioneers stated: "The most unusual aspect of our card is its rarity. No such card with police provenance has been offered for sale at auction.
"The great beauty of the card is that with its police provenance it is a unique Ripper item for sale.
"No one can prove it is the Ripper himself, but equally no one can prove it is not."