Retired detective interviewed by the Daily Telegraph in October 1888 for his insights into the mind of the Whitechapel murderer. According to the Telegraph, Knowles was previously a member of the New York division of the Pinkerton agency, and later employed by the Glasgow police. No additional biographical information has yet been unearthed.
The fictional book Quest of the Mountain Men contains a character named "Albert Knowles" who is also described as a "Pinkerton man," but whether this character is based on any historical figure has yet to be determined.
A.E. Knowles should not be confused with Dan Farson's 1950s informant, named "A. Knowles", nor does there appear to be any relation to Enoch Knowles, a Darlaston labourer arrested in the 1930s for writing obscene letters, one of which was signed "Jack the Ripper of Whitechapel."
The full-text of A.E. Knowles' interview with the Daily Telegraph was published in their issue of 9 October 1888:
"The following opinions are those of Mr. A. E. Knowles, who for many years was employed in America and in Great Britain in detective work. Mr. Knowles was a member of the Pinkerton private inquiry combination of New York, whose services are frequently retained by the Government of the United States, and subsequently he had a successful experience in the detective department of the Glasgow police. Latterly, having virtually retired from business, he has been resident in the metropolis, with which he is thoroughly familiar. Mr. Knowles, as an expert in criminal investigation, is convinced that the Whitechapel murderer is insane, because of the absence of motive and of the character of the mutilations which he perpetrates. That he is a coward is evidenced by the class of victims chosen, and the fact that these women must have been in a state of drink at the time of their death. The manner in which the culprit has eluded notice, and the way in which he guarded against suspicion both before and after the murders, shows that he is possessed of considerable intelligence, probably the cunning of the lunatic. The assassin must have means at his command by which he is enabled to change his abode, personal appearance, and dress at pleasure. Time has been wasted in looking amongst the rags of Whitechapel for him, and the step which should have been taken at the outset was to have sent information to every railway station and port within reasonable distance of London immediately after the first murder was reported. By these means every passenger out of the City on the Sunday would have been scrutinised. The police lost their opportunity at the time of the Hanbury-street murder. Had they adopted the same precautions as prevail now the man would have been captured. The murderer, Mr. Knowles believes, is not now in the East of London, and, the hue-and-cry being so great, he doubts his presence in England. Great precautions are necessary, as during a period of panic the imitative faculty is strong, as already shown by the commission of a similar crime at Gateshead. There are circumstances which justify the inference that the Whitechapel murderer is respectably connected, living alone in chambers, or possibly with a relative - and if the latter it cannot be expected that a mother or sister would hand him over to justice, but would do all she could to get him out of the country. Ten or twelve years ago a case occurred in America in which two children, both girls under fourteen, were found murdered. They were enticed from the streets at different times and their throats were cut. One body was thrown into a garden and the other into a piece of waste ground. The author of the crime could not be discovered. A little girl was sent out as a decoy, and was watched meanwhile by detectives. For days nothing occurred, but at last a man to whom suspicion pointed drew near. The success of the stratagem was marred, however, by the fear of the detectives that he might kill the girl before their eyes, and they dared not hide themselves. The individual suspected made off, but he was "shadowed," and his address and connections were discovered. Owing to the political system prevailing the chief of the police could not be induced to issue a warrant, as, legally, there was absolutely no evidence. In England the man would have certainly been detained for inquiries. Every effort to interview him failed, and his family sent him out of the country, it is alleged, to avoid further inquiry. Mr. Knowles thinks that the English detective system might be reinforced by a small body of well-paid, well-dressed men of good education and proven intelligence, and of not more than 5ft. 7in. in height, as a person over that stature attracts attention. Mr. Pinkerton, in choosing his staff, invariably gives the preference to short men. Detectives need not of necessity be policemen."