...The mystery, however, that baffled the police more than anything was how the murderer and the victim managed to get into the alley under the eyes of the watching police. It was clear that the couple had not been in any of the houses, and they were not known to any of the residents. Therefore they must have passed into the alley from the Whitechapel Road, and the two police officers were positive that in the four hours of their vigil not a soul had entered the alley. White had his own suspicions regarding the truth of this declaration, and his suspicions were shared by Sir Robert Anderson, who afterwards in comparing notes with White, expressed the opinion that the murderer and his victim had entered the close during the temporary absence of the two watching policeman. The men afterwards admitted that they had gone away for not more than a minute. It was a very short absence undoubtedly, but it was long enough to give the murderer time to walk into the alley with his victim...
In June/July 1888 and 1889 there were very cold nights (White´s bitter cold night).
The crime scene, described via White, is a mystery for me. But I would not rule out Castle Alley. I simply do not know.
I´m looking for tiny details which may show that the Police had an ongoing interest in someone who worked in Butchers Row.
Times, 3 April 1889:
Detective Sergeant Pentin had followed a suspicious character who entered 5 Duke Street, and was able to "communicate with" Sagar, who helped him to search the premises and arrest the man.
We also do know that Sagar was on Duty opposite Butchers Row in December 1890.
Who knows, maybe there was a connection between the two officers at the entrance of Castle Alley and Butchers Row in July 1889. If the police were interested in a suspect from Butchers Row over a long period, then, this suspect must have been very important for the police. The dates I mentioned would rule out David Cohen and Jacob Levy as the Butchers Row suspect. (Apart from "Kosminski" I´m also very interested in David Cohen, Jacob Levy, Cox´ suspect and the Butchers Row suspect -Sagar´s suspect-).
But that´s speculation, nothing else than that...