 The " Saucy Jacky " postcard was postmarked 1 October 1888 and was received the same day by the Central News Agency . The handwriting was similar to the " Dear Boss " letter . It mentions that two victims were killed very close to one another : " double event this time " , which was thought to refer to the murders of Stride and Eddowes . It has been argued that the letter was mailed before the murders were publicised , making it unlikely that a crank would have such knowledge of the crime , but it was postmarked more than 24 hours after the killings took place , long after details were known and being published by journalists and talked about by residents of the area . 
