The victims were women allegedly earning income as prostitutes. The murders were perpetrated in public or semi-public places at night or in the early morning. The victim's throat was cut, after which the body was mutilated. Theories suggest the victims were first strangled in order to silence them, which also explained the reported lack of blood at the crime scenes. The removal of internal organs from three of the victims led some officials at the time of the murders to propose that the killer possessed anatomical or surgical knowledge.
Newspapers, whose circulation had been growing during this era, bestowed widespread and enduring notoriety on the killer owing to the savagery of the attacks and the failure of the police to capture the murderer, sometimes missing him at the crime scenes by mere minutes.Because the killer's identity has never been confirmed, the legends surrounding the murders have become a combination of genuine historical research, folklore and pseudohistory. Over the years, many authors, historians, and amateur detectives have proposed theories regarding the identity (or identities) of the killer and his victims.
During the mid-1800s, England experienced a rapid influx of primarily Irish immigrants, swelling the populations of both the largely poor English countryside and England's major cities. From 1882, Jewish refugees escaping the pogroms in Tsarist Russia and eastern Europe added to the overcrowding and the already worsening work and housing conditions. London, and in particular the East End and the civil parish of Whitechapel, became increasingly overcrowded resulting in the development of a massive economic underclass. This endemic poverty drove many women to prostitution. In October 1888 the London Metropolitan Police estimated that there were 1,200 prostitutes "of very low class" resident in Whitechapel and about sixty-two brothels. The economic problems were accompanied by a steady rise in social tensions. Between 1886 and 1889 demonstrations by the hungry and unemployed were a regular feature of London policing.
The majority of murders, and those most often attributed to "Jack the Ripper", all occurred in the latter half of 1888, though the series of brutal killings in Whitechapel persisted at least until 1891. A number of the murders entailed extremely gruesome acts, such as mutilation and evisceration, which were widely reported in the media. Rumours that the murders were connected intensified in September and October, when a series of extremely disturbing letters were received by various media outlets and Scotland Yard, purporting to take responsibility for some or all of the murders. One letter, received by George Lusk of the Whitechapel Vigilance Committee, included a preserved human kidney. Owing in large part to the extraordinarily brutal character of the murders, and to media treatment of the events, the public increasingly came to believe in a single serial killer terrorizing the residents of Whitechapel, nicknamed "Jack the Ripper" after the signature on a postcard received by the Central News Agency. Although the investigation was unable to conclusively connect the later killings to the murders of 1888, the legend of Jack the Ripper solidified.