Attacks ascribed to the Ripper typically involved female prostitutes from the slums whose throats were cut prior to abdominal mutilations. The removal of internal organs from at least three of the victims led to proposals that their killer possessed anatomical or surgical knowledge. Rumors that the murders were connected intensified in September and October 1888, and letters from a writer or writers purporting to be the murderer were received by media outlets and Scotland Yard. The "From Hell" letter, received by George Lusk of the Whitechapel Vigilance Committee, included half of a preserved human kidney, supposedly from one of the victims. Mainly because of the extraordinarily brutal character of the murders, and because of media treatment of the events, the public came increasingly to believe in a single serial killer known as "Jack the Ripper".
Extensive newspaper coverage bestowed widespread and enduring international notoriety on the Ripper. An investigation into a series of brutal killings in Whitechapel up to 1891 was unable to connect all the killings conclusively to the murders of 1888, but the legend of Jack the Ripper solidified. As the murders were never solved, the legends surrounding them became a combination of genuine historical research, folklore, and pseudohistory. The term "ripperology" was coined to describe the study and analysis of the Ripper cases. There are now over one hundred theories about the Ripper's identity, and the murders have inspired multiple works of fiction.