Given the amount of police time and resources that were wasted by the numerous Jack the Ripper letters, a surprisingly small number of those responsible for them were actually located by the police. As far as the Dear Boss- Yours Truly Jack the Ripper letter goes, no-one was ever officially named as being its author, although various police officers were adamant that the missive was the work of a London journalist.
On the 10th October 1888 Sir Charles Warren, the Metropolitan Police Commissioner, wrote to the Home Office to give his opinion on whether or not the "Dear Boss" letter was the work of the killer:-
At present I think the whole thing a hoax but of course we are bound to try & ascertain the writer in any case.”
Writing in his memoirs just before they were published in 1910 Sir Robert Anderson, who at the time of the murders was the Assistant Commissioner and head of the Criminal Investigation Department at Scotland yard, was emphatic that the "Dear Boss" letter was a prank missive, and not the work of the killer. Indeed, he even claimed that the police were aware of the author's identity.
I will only add here that the "Jack the Ripper" letter which is preserved in the Police Museum at New Scotland Yard is the creation of an enterprising London Journalist.”
In 1913 the journalist George Sims wrote to Detective Chief Inspector John George Littlechild, who had been the head of Special Branch when the Jack the Ripper murders were taking place, to ask for information about the case. In his reply Littlechild stated that:-
With regard to the term 'Jack the Ripper' it was generally believed at the Yard that Tom Bullen of the Central News was the originator, but it is probable Moore, who was his chief, was the inventor. It was a smart piece of journalistic work. No journalist of my time got such privileges from Scotland Yard as Bullen. Mr James Munro when Assistant Commissioner, and afterwards Commissioner, relied on his integrity. Poor Bullen occasionally took too much to drink, and I fail to see how he could help it knocking about so many hours and seeking favours from so many people to procure copy. One night when Bullen had taken a 'few too many' he got early information of the death of Prince Bismarck and instead of going to the office to report it sent a laconic telegram 'Bloody Bismarck is dead.' On this I believe Mr Charles Moore fired him out.”
In fact Littlechild was wrong about the name of his "writer suspect" as it was Thomas J. Bulling, not Tom Bullen, who worked at the Central News Agency.
Bullen was the man who, not long after the "Dear Boss" letter had been made public, forwarded a handwritten copy of another missive - which was dated October 5th and which was signed 'Jack the Ripper' - to the police. he also forwarded the envelope that the letter had arrived in commenting that it was "in the same handwriting as the previous communications."
However, he only enclosed a hand-written copy of the letter itself, which might suggest that he was finding it a little difficult to disguise his own handwriting?
The letter consisted of a series of biblical quotes and contained more threats including that the killer was about to strike again and that he would send a body part, this time a bit of the face, to the police :-
I must get to work tomorrow treble event this time yes yes three must be ripped. will send you a bit of face by post I promise this dear old Boss.
The police now reckon my work a practical joke well well Jacky’s a very practical joker ha ha Keep this back till three are wiped out and you can show the cold meat.”
Interestingly, the police were evidently becoming convinced that the homicidal maniac who was murdering prostitutes in the East End of London was not the same person who was writing these taunting letters and signing them Jack the Ripper. Indeed, it appears that they actually asked the Central News Agency not to release the contents of the 5th October letter to the general public and, as a result, it received very little coverage in the media.