 Historically , the belief that these five crimes were committed by the same man is derived from contemporary documents that link them together to the exclusion of others . In 1894 , Sir Melville Macnaghten , Assistant Chief Constable of the Metropolitan Police Service and Head of the Criminal Investigation Department ( CID ) , wrote a report that stated : " the Whitechapel murderer had 5 victims — & 5 victims only " . Similarly , the canonical five victims were linked together in a letter written by police surgeon Thomas Bond to Robert Anderson , head of the London CID , on 10 November 1888 . Some researchers have posited that some of the murders were undoubtedly the work of a single killer but an unknown larger number of killers acting independently were responsible for the others . Authors Stewart P. Evans and Donald Rumbelow argue that the canonical five is a " Ripper myth " and that three cases ( Nichols , Chapman , and Eddowes ) can be definitely linked but there is less certainty over Stride and Kelly . Conversely , others suppose that the six murders between Tabram and Kelly were the work of a single killer . Dr Percy Clark , assistant to the examining pathologist George Bagster Phillips , linked only three of the murders and thought that the others were perpetrated by " weak @-@ minded individual [ s ] ... induced to emulate the crime " . Macnaghten did not join the police force until the year after the murders , and his memorandum contains serious factual errors about possible suspects . 
