Having murdered Elizabeth Stride and Catherine Eddowes, on the 30th September 1888, the Whitechapel Murderer fled eastwards from Mitre Square and headed into the East End of London where he left a clue in a doorway in Goulston Street, a short walk away from Mitre Square.
He had now murdered twice in less than an hour and was, no doubt, well aware that the area would soon be teeming with police officers, each one of them intent on hunting him down and catching him.
Yet, he didn't head to the relative safety of the streets to the west, the north or the south of Mitre Square, but rather he went into the streets where much of the activity was directed to his capture.
This would suggest that he was heading for the safety of his home or lodging and that he was, therefore, a local man living in the heart of the area.
The strangest thing of all about the killer's escape from Mitre Square is that he appears to have slipped past several police officers without either being noticed or arousing any suspicion.
We know, for example, that at the moment that Catherine Eddowes was leading her murderer-to-be into Mitre Square, three City Detectives, Daniel Halse, Robert Outram and Edward Marriot, were busily orchestrating plain clothes patrols along the City's eastern fringe.
Yet the murderer had, apparently, managed to slip past them undetected as he headed back into the East End having slaughtered Catherine Eddowes.
Daniel Halse was over by St Botolph's Church when he learnt of the murder at just before 2am.
Hurrying to Mitre Square, he gave instructions to the constables present to head off and search the neighbourhood.
He then set off to make his own search, heading first for Middlesex Street, from which he turned into Wentworth Street, where he stopped to question two men he encountered, both of whom gave him a satisfactory account of their movements, and so he allowed them to continue on their way.
He then passed through Goulston Street at around 2.20am where, having found nothing out of the ordinary, he doubled back and returned to Mitre Square.
On arrival, he discovered that the body had been taken to the mortuary in Golden Lane, so he made his way there and, on arrival, he was informed that a fragment of the woman's apron had, apparently, been taken away by her killer.
The missing segment of the apron was found by PC Alfred Long as he patrolled his beat along Goulston Street at 2.55am that morning.
Walking past the doorway which led to the staircases of 108 to 119 Wentworth Model Dwellings, he noticed a portion of apron lying on the floor inside the doorway.
On closer inspection, he discovered that it was covered with blood and faeces, and noticed other marks which suggested that the blade of a knife had been wiped on it.
PC Long had, in fact, walked past the same doorway at 2.20am, at more or less the same time that Daniel Halse had also passed through Goulston Street, and, like Halse, he had seen nothing out of the ordinary. Indeed, he was emphatic that he would, most certainly, have noticed had the piece of apron been there then and he was, therefore, sure that it hadn't been.
The apron is the only real clue that Jack the Ripper left behind, and it tells us much about the killer's intentions and appearance as he fled the scene of his latest atrocity, but, at the same time, it also raises other questions that, in some ways, muddy the waters even further!
It is a clue in so much as it reveals to us the direction that the ripper took as he fled from Mitre Square in the wake of the murder of Catherine Eddowes.
There can be no doubt that he was going to ground as he headed away from the murder scene, so the location of the bloodied fragment suggests that he was heading to a home, or bolt hole, situated in the East End of London.
The apron also answers the question of his appearance as he fled from the scenes of his atrocities.
There is a common belief that he must have been drenched in blood having carried out such brutal and gruesome murders.
But this was, probably, not the case.
Indeed, the apron tells us how much visible and incriminating blood he would have had upon his person.
Since the available evidence suggests that the ripper asphyxiated his victims before carrying out his repellent mutilations, their hearts would have all but stopped beating by the time he cut their throats and thus he would have avoided the arterial spurt that would have resulted in him becoming heavily bloodstained when he cut the carotid artery.
It should also be remembered that his victims, being prostitutes, went with him into the dark corners of squares and passageways for the purpose of sexual intercourse. If he was wearing a large overcoat they would have had no suspicion should he opt to unbutton or remove it. Indeed, they would, doubtless, have been more suspicious had he opted to keep it on.
Having carried out the murder he may have had blood on his shirt, jacket and trousers but, by putting the coat back on, he would have been able to conceal many of the bloodstains, and they would have remained hidden until he got home and was able to clean himself up at his leisure.
The apron reveals just how much visible blood he did have on his person for, as he made his way through the streets, he would, undoubtedly, have had blood on his hands and on the blade of his knife and would have been anxious to wipe this away as soon as possible.
Had he stopped in the streets and wiped away the evidence, he may have been noticed. He required some cover to perform this task, and a recessed and dark doorway, such as the one in Goulston Street, would have provided sufficient privacy for him to wipe his hands and the blade of his knife without attracting any attention to his nefarious task.
Once he was certain that he was clean enough, he would have dropped the apron and continued home.
But, if the apron solves the mystery of why the killer was able to escape without anyone noticing any bloodstains, it throws up another puzzle in that its presence in that particular doorway suggests that he lingered in the immediate vicinity of his crime for much longer than he actually needed to.
The journey from Mitre Square to Goulston Street takes a little under ten minutes at a brisk pace.
Daniel Halse had walked it in twenty or so minutes, and he was on the look out for suspicious looking characters, and had even stopped to question the two men he had encountered en route.
There are, admittedly, several possible routes that he could have taken, but they can all be done at a rapid pace in around ten minutes or less.
If Long and Halse were correct in their assertion that the portion of apron hadn't been there at 2.20am, then the murderer had loitered in the area for anywhere between 35 minutes and an hour, during which time the police were fanning out into the area to search for him, and were stopping and questioning any man they met.
So where was the killer while all this was happening? Was he hiding in one of the empty warehouses along the route? If so why hadn't he dropped the apron there? Surely his survival instinct would have instantly kicked in after the crime, and his overwhelming desire would have been to get away from the danger of capture as quickly as he possible.
Is it possible that he had, in fact, gone home, and then returned to the streets, devoid of bloodstains, to drop the apron into the doorway, possibly to taunt the police?
The honest truth is that we will never now know the answer to this puzzling question.
Long's first thought, on discovering the portion of apron, was that someone may have been attacked and could at that very moment be lying injured or dead on a staircase or landing inside the dwellings.
So he stood up, intending to search the block and, as he did so, he noticed a scrawled chalk message on the wall directly above the apron. It read "The Juwes are the men that will not be blamed for nothing."
Moments later another officer arrived at the scene, and Long asked him to guard the building - telling him to keep a careful watch on anybody entering or leaving it – whilst he took the portion of apron round to Commercial Street Police Station and handed over to an inspector.
Soon, officers of the Metropolitan Police were gathering around the doorway and were gazing at the graffito with feelings of great trepidation.
Mindful of the strong feelings of anti-Semitism that had surfaced in the area in the wake of the Leather Apron scare, and realizing that Wentworth Model Dwellings not only stood in a largely Jewish locality, but was also inhabited almost exclusively by Jews, the Metropolitan Police began to fear that if the message was left, it could lead to a resurgence of racial unrest in the district and the consequences could be dire.
They were therefore anxious to erase the message, and to do so sooner rather than later.
But both the portion of apron and the graffito pertained to a murder investigation being carried out by the City Police, detectives of which had soon crossed the boundary and were also gathering around the doorway.
They were not so keen to erase what they saw as an important clue in their investigation and the two forces clashed over what should be done about the graffito.
The City Police were adamant that it should be photographed. The Metropolitan Police pointed out that that would mean waiting until it was light, by which time gentile purchasers would be arriving in their thousands to purchase from the Jewish stallholders at the Petticoat Lane and Goulston Street Sunday markets.
Since there was no way of keeping it hidden from these crowds, the Metropolitan Police were convinced the result might be a full scale riot against the Jews.
Daniel Halse suggested a compromise whereby only the top line, - "The Juwes are" - would be erased.
But, as Superintendent Arnold, of the Metropolitan Police, later pointed out in a report, "Had only a portion of the writing been removed the context would have remained."
The bickering was still going on when Sir Charles Warren arrived at the scene between 5 and 5.30am.
Since the doorway stood on Metropolitan Police territory, his word was final, and he immediately concurred with his officers that leaving the graffito any longer would lead to far greater crimes against innocent Jews.
So he ordered that the message be erased without delay, and before any photograph of it could be taken.
It would prove once of the most controversial orders he gave in the entire investigation and Major Smith, the acting City Police Commissioner, considered it a huge blunder and could barely disguise his contempt for Warren's actions.
On the 6th November, in a report to the Home office, Warren defended his action:-
...it was just getting light, the public would be in the streets in a few minutes, in a neighbourhood very much crowded by Jewish vendors and Christian Purchasers from all parts of London...The writing was on the jamb of the open archway or doorway visible to anybody in the street and could not be covered up without danger of the covering been torn off at once. A discussion took place whether the writing could be left covered up or otherwise...for an hour until it could be photographed; but after taking into consideration the excited state of the population in London...the strong feeling which had been excited against the Jews, and the fact that in a short time there would be a large concourse of the people in the streets, and having before me a report that if it was left there the house was likely to be wrecked (in which from my own observation I entirely concurred) I considered it desirable to obliterate the writing at once...I do not hesitate to say that if the writing had been left there would have been an onslaught upon the Jews, property would have been wrecked, and lives would probably have been lost..."
In fairness to Sir Charles Warren, many of those who saw the graffito commented that it looked faded, as though it had been there for some time.
Also, it seems somewhat unlikely that, having taken the trouble to clean his hands to obliterate incriminating bloodstains, the ripper would have then risked lingering in the doorway long enough to chalk the message on the wall, knowing that, at any moment, a passing police man might spot him.
The probability is that the message was already there, possibly left over from the anti-Semitic unrest that had swept the area in the wake of the Leather Apron scare, and that it was a complete coincidence that the ripper had chosen that same doorway in which to clean himself up and leave behind his only clue.
Given the events of a few weeks previous, Warren was probably justified in his belief that erasing the message would spare innocent Jews from becoming the targets of avenging gentile mobs and he probably made the right judgment call based on the information immediately available to him.
With hindsight, however, it is interesting to note that, because of the controversy over Warren's actions, the Goulston Street graffito was widely reported, and yet the wide-scale anti-Semitism that Warren so feared did not break out again.