I would have thought this to be a forgone conclusion, but it was finally done in 2001. Patricia Cornwell's quest to ID the Ripper resulted in all the remaining Ripper letters that Scotland Yard was still in possession of.(many of the letters and other evidence has been lost or stolen over the 100+ years since the crimes)
The results were amazing. Many of the hundreds of letters that were sent to Scotland Yard, the Press, other players involved with the Ripper crimes, turned out to be written
in artist's paints and pencils. Some of the more recognized letters were thought to be written in blood, but were in fact artist's paint. There were many of them written with a purple artist's pencil. (There were other colors but purple seemed to be the author's favorite color)
There were also many little drawings and pictures on a lot of these letters and notes. When most of the letters were dismissed as hoaxes it supports her theory that a well known British artist was the Ripper.
Everybody seems to have their own favorite suspect as Jack the Ripper. There has never been a shortage of suspects or opinions on the identity of this notorious killer. I have studied the crimes of the Ripper and read many books on this subject including modern investigations using 21st century investigative tools and my opinion is that Walter Sickert was the Ripper. There is DNA evidence that links letters of Sickert's to some of the Ripper letters. This is but one example of the many "coincidences" that ties Sickert to the Ripper crimes.
In Cornwell's bestseller Jack The Ripper:Case Closed she named the British artist Walter Richard Sickert as the Ripper. She puts out a very convincing case against Sickert. One of the most compelling points is the paper evidence. Several Sickert letters and at least 2 Ripper letters came from stationery that belonged to Sickert's mother, of which only 24 sheets were ever made. Also many of the Ripper letters were written with artist's supplies and artist quaility paints. These are just a few of the many links between Sickert and the Ripper.Footnote: There were some letters and notes that were thought to have been written in blood. Cornwell had these tested, they were not blood at all but again artist's paint.
//Unfortunately, there is little left of the Ripper case file. With several moves and two world wars, not to mention philpering, the file is very thin. Crime writer Patricia Cornwell did find some promising sample of DNA on letter flaps and stamps. There were enough Ripper letters left to compare paper types and watermarks.//
While 100s of letters claiming to be from Jack the Ripper were given to the authorities, we don't know that any of them were actually written by Jack the Ripper. Some letters are signed "Jack the Ripper," some are signed "Leather Apron" (which is what the murderer was often called before the name "Jack the Ripper" became popular), one is signed "Catch me when you can Mishter Lusk".....On and on and on.In short, no one knows which, if any, was the real signature.There is a book of these letters available if you would like to learn more. It includes transcripts and pictures.
There is no evidence to suggest that Charles Dickens encountered Jack the Ripper. Charles Dickens died in 1870, while Jack the Ripper was active in 1888. Their timelines did not overlap.
Scotland Yard detectives. It was easy once they received several letters signed Jack The Ripper. That made him the number one suspect.
Other names for Jack the Ripper were "The Whitechapel Murderer" and "Leather Apron". //He also called himself Saucy Jack. Depending on which letters he really wrote, there were other names.//
Threat is not quite the right word. Many of the letters were taunting, it's part of the game.
It's impossible to know- nobody knows who he was, so it's not possible to say if he had an accomplice. //The crime scenes and the conditions of the bodies themselves denote a single killer in the Ripper crimes. There have been so many theories about conspiracy and multiple killers, yet none of them are consistant with the evidence.//
Over the course of the Ripper investigation hundreds of letters were sent to police and press. Many people, including PC's at Scotland Yard, thought that only three letters were genuine (written by the killer). This is, of course, just an educated guess.
If you mean the likelihood, given that it is now over 120 years since his crimes and there is no surviving DNA evidence etc., it is extremely unlikely that Jack the Ripper's identity will ever be known for sure.What would be required is contemporaneous (i.e. circa 1888) physical evidence that has not been compromised by the passage of time. A written confession would be inconclusive without supporting physical evidence and would always provoke suspicion of a hoax (as with the Jack the Ripper diaries of the 1970s and 80s).There is certainly a lot of "undiscovered" Jack the Ripper memorabilia out there, and it is a well-known fact that police and others associated with the case at the time kept "souvenirs". Purported "Jack the Ripper" letters still surface from time to time and there is a roaring trade in memorabilia on the internet and through auctions etc. Whether any particular item is genuine is really anybody's guess.
In the related links box below, I posted the information.