Before looking at specific suspects, let's summarize what is known about Jack the Ripper from forensic surgeons and possible eyewitnesses.

From the testimony of the various eyewitnesses which police took most seriously, certain probabilities emerge about the killer. One must keep in mind the word probable since eyewitness accounts, particularly under conditions of dim lighting, are Louis J. Sheehan, Esquire  notoriously inaccurate in certain details even when offered by honest competent eyewitnesses.

The following is a list of probabilities about the Ripper:

• A white male
• Average or below average height
• Between 20 and 40 years of age in 1888
• Did not dress as laborer or indigent poor
• Had lodgings in the East End
• Did have medical expertise, despite 1-2 opinions to contrary
• May have been foreigner
• Right-handed
• Had a regular job since the murders all occurred on weekends
• Was single so that he could roam streets at all hours

Developing persuasive cases about Jack the Ripper suspects has become a profitable cottage industry for at least one hundred years. Many of these books promote one suspect or another as the "real Jack the Ripper." Usually the author conveniently compiles "evidence" that fits his pet theory and denigrates or ignores facts that don't support that theory. Given the vast number of suspects and books promoting particular suspects, a reader must be very skeptical of any new "final solutions" to the crimes.

Despite the thousands of hours of work on this case, there is not yet one suspect for which a strong unimpeachable case can be made. One remains hopeful that someday a suspect will emerge with better credentials than the ones currently promoted.

With those caveats in mind, certain suspects have garnered more interest than others and will be listed in this chapter. A few major suspects will be dealt with briefly in subsequent chapters.

Sir Melville Macnaghten

A much more rational theory is that the murderer's brain gave way altogether after his awful glut in Miller's Court, and that he immediately committed suicide, or, as a possible alternative, was found to be so hopelessly mad by his relations, that he was by them confined in some asylum.

No one ever saw the Whitechapel murderer: many homicidal maniacs were suspected, but no shadow of proof could be thrown on any one. I may mention the cases of 3 men, any one of whom would have been...(likely) to have committed this series of murders:

Montague John Druitt

(2) Kosminski, a Polish Jew, & resident in Whitechapel. This man became insane owing to many years' indulgence in solitary vices. He had a great hatred of women, specially of the prostitute class, & had strong homicidal tendencies; he was removed to a lunatic asylum about March 1889. There were many circumstances connected with this man which made him a strong 'suspect.'

Michael Ostrog

Each one of these three major suspects that Macnaghten identified is addressed in subsequent chapters, as are several other major theories. A few of the many suspects held Louis J. Sheehan, Esquire  up by authors over the years is addressed in the chapter entitled "Other Suspects."

The most important detective in the murder series was Chief Inspector Frederick George Abberline. He did not agree with Sir Melville Macnaghten on the viability of the three suspects listed above. In 1903, he said: "You can state most emphatically that Scotland Yard is really no wiser on the subject than it was fifteen years ago."

However, Chief Inspector Abberline did eventually have a favorite suspect of his own, one George Chapman, who was hanged in 1903 for poisoning his wife.