When:
After the double murder of Elizabeth Stride and Catherine Eddowes on 30 September 1888.

Connection to the Ripper case:
Constable Alfred Long of the Metropolitan Police Service discovered a dirty, bloodstained piece of an apron in the stairwell of a tenement, 108 to 119 Model dwellings, Goulston Street, Whitechapel. The cloth was later confirmed as being a part of the apron worn by Catherine Eddowes.

Above it, there was writing in white chalk on either the wall or the black brick jamb of the entranceway. Long reported that it read, “The Juwes are the men that will not be blamed for nothing.”

Since the murder of Mary Ann Nichols on 31 August 1888, rumours had been circulating that the killings were the work of a Jew dubbed “Leather Apron”, which had resulted in anti-Semitic demonstrations.