[2] Assistant Police Commissioner Robert Anderson recommended Whitechapel to "those who take an interest in the dangerous classes" as one of London's prime criminal "show places".
[9] Police work and criminal prosecutions at the time relied heavily on confessions, witness testimony, and apprehending perpetrators in the act of committing an offence or in the possession of obvious physical evidence that clearly linked them to a crime.
[13] On Tuesday 3 April 1888, following the Easter Monday bank holiday, 45-year-old prostitute Emma Elizabeth Smith was assaulted and robbed at the junction of Osborn Street and Brick Lane, Whitechapel, in the early hours of the morning.
[18] Walter Dew, a detective constable stationed with H Division, later wrote that he believed Smith to be the first victim of Jack the Ripper,[19] but his colleagues suspected her murder was the work of a criminal gang.
[25] On the basis of statements from a fellow prostitute, and PC Thomas Barrett who was patrolling nearby, Inspector Reid put soldiers at the Tower of London and Wellington Barracks on an identification parade, but without positive results.
On the same day, James Monro resigned as the head of the Criminal Investigation Department (CID) over differences with Chief Commissioner of the Metropolitan Police Sir Charles Warren.
[33][34] Suspicions of a serial killer at large in London led to the secondment of Detective Inspectors Frederick Abberline, Henry Moore and Walter Andrews from the Central Office at Scotland Yard.
[36] However, by the time the inquest into Nichols's death had concluded, a fourth woman had been murdered, and Baxter noted "The similarity of the injuries in the two cases is considerable.
"[37] The mutilated body of the fourth woman, Annie Chapman, was discovered at about 6:00 am on Saturday 8 September on the ground near a doorway in the back yard of 29 Hanbury Street, Spitalfields.
The pathologist, George Bagster Phillips, was of the opinion that the murderer must have possessed anatomical knowledge to have sliced out the reproductive organs in a single movement with a blade about 6–8 inches (15–20 cm) long.
[47] Samuel Montagu, the Member of Parliament for Whitechapel, offered a reward of £100 (roughly £14,000 as of 2025) after rumours that the attacks were Jewish ritual killings led to anti-Semitic demonstrations.
[48] Local residents founded the Whitechapel Vigilance Committee under the chairmanship of George Lusk and offered a reward for the apprehension of the killer—something the Metropolitan Police (under instruction from the Home Office) refused to do because such a move could lead to false or misleading information.
[58] At 1:45 am, Catherine Eddowes's mutilated body was found by PC Edward Watkins at the south-west corner of Mitre Square, in the City of London, about 12 minutes walk from Berner Street.
[63] The first doctor at the scene, local surgeon George William Sequeira, disputed that the killer possessed anatomical skill or sought particular organs.
[66] At 3 am, a blood-stained fragment of Eddowes's apron was found lying in the passage of the doorway leading to 108 to 119 Goulston Street, Whitechapel, about a third of a mile (500 m) from the murder scene.
[74] A grocer, Matthew Packer, implied to private detectives employed by the Whitechapel Vigilance Committee that he had sold some grapes to Stride and the murderer; however, he had told police that he had shut his shop without seeing anything suspicious.
[79] Joseph Lawende passed through Mitre Square with two other men shortly before Eddowes was murdered there, and may have seen her with a man of about 30 years old, who was shabbily dressed, wore a peaked cap, and had a fair moustache.
[88] On the same day, the psychic Robert James Lees visited Scotland Yard and offered to track down the murderer using paranormal powers; the police turned him away and "called [him] a fool and a lunatic".
[92] On Friday 9 November, prostitute Mary Jane Kelly was murdered in the single room where she lived at 13 Miller's Court, behind 26 Dorset Street, Spitalfields.
[99] The coroner for North East Middlesex, Dr Roderick Macdonald, MP,[100] presided over the inquest into Kelly's death at Shoreditch Town Hall on 12 November.
[104] On 10 November, the police surgeon Thomas Bond wrote to Robert Anderson, head of the London CID, detailing the similarities between the five murders of Nichols, Chapman, Stride, Eddowes and Kelly, "no doubt committed by the same hand".
[107] On Thursday 20 December 1888, a patrolling constable found the strangled body of 26-year-old prostitute Rose Mylett in Clarke's Yard, off Poplar High Street.
[108] Mylett (born Catherine Milett and known as Drunken Lizzie Davis[109] and Fair Alice Downey[110]) had lodged at 18 George Street, as had Emma Smith.
[125] Extensive bruising about the victim's back, hip, and arm indicated that she had been severely beaten shortly before her death, which had occurred approximately one day prior to the discovery of her torso.
[126] Chief Inspector Donald Swanson and Commissioner James Monro noted that the presence of blood within the torso indicated that death was not from haemorrhage or cutting of the throat.
[135][136] Experts on the murders—colloquially known as "Ripperologists"—such as Stewart Evans, Keith Skinner, Martin Fido, and Donald Rumbelow, discount any connection between the torso and Ripper killings on the basis of their different modi operandi.
[137] Monro was replaced as Commissioner by Sir Edward Bradford on 21 June 1890, after a disagreement with the Home Secretary Henry Matthews over police pensions.
A high-profile investigation by Swanson and Moore into Sadler's past history and his whereabouts at the time of the previous Whitechapel murders indicates that the police may have suspected him to be the Ripper.
[147] The poor of the East End had long been ignored by affluent society, but the nature of the Whitechapel murders and of the victims' impoverished lifestyles drew national attention to their living conditions.
[149][150] On 24 September 1888, George Bernard Shaw commented sarcastically on the media's sudden concern with social justice in a letter to The Star newspaper:[151] Whilst we conventional Social Democrats were wasting our time on education, agitation and organisation, some independent genius has taken the matter in hand, and by simply murdering and disembowelling ... women, converted the proprietary press to an inept sort of communism.Acts of Parliament, such as the Housing of the Working Classes Act 1890 and the Public Health Amendment Act 1890, set minimum standards for accommodation in an effort to transform degenerated urban areas.