The "From Hell" letter (also called the "Lusk letter") is a letter that was posted in 1888, along with half a human kidney, by a person who claimed to be the serial killer known as Jack the Ripper. The murderer killed and mutilated at least five female victims in the Whitechapel area of London over a period of several months, the case attracting a great deal of attention both at the time and since. The exact number of victims has never been conclusively proven, and the identity of the perpetrator of the Whitechapel killings has likewise remained unsolved.