A phrase taken from the last of the three letters sent to Scotland Yard police from the infamous serial killer "Jack the Ripper." It is especially famous for its gruesome contents: a letter to the police chief and half of a kidney of one of his victims (the letter claims he ate the other half).
The text of the letter reads:
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