On October 15th of 1888, Mr George Lusk, Chairman of the Whitechapel Vigilance Committee—a group of concerned citizens who actively searched for the person responsible for a spate of killings known as the “Whitechapel murders”—received this chilling letter from someone claiming to be infamous serial killer Jack the Ripper. It was sent along with a small box, the contents of which was later determined to be half a human kidney, preserved in wine. Catherine Eddowes, Jack the Ripper's fourth victim, was thought to be the organ's previous owner; according to the note, the remainder of her kidney had been fried and eaten.
(Source: The Royal London Hospital Archives; Image: George Lusk, via Wikipedia.)
I send you half the Kidne I took from one women prasarved it for you tother piece I fried and ate it was very nise. I may send you the bloody knif that took it out if you only wate a whil longer
Catch me when you can Mishter Lusk