After discovering that the phrase "man is the most dangerous animal of all" from the Zodiac Killer's 408 cipher was uttered by Merian C. Cooper, the associate producer of "The Most Dangerous Game" movie in 1932, which could only reasonably have been found by diligently trawling through microfiche reels from newspapers of the day, I wanted to see if the author of the Confession letter employed the same technique. By finding a commonality of approach between the 408 cipher and Confession letter authors, it may shed light on the idea of one mind and one person responsible for the communications in 1966 and 1969. This is the first step in determining whether the Zodiac Killer was responsible for "riverside activity" or "riverside murder".
I then looked at the seemingly contrived section of the Confession letter where it stated "I said it was about time. She asked me "about time for what". I said it was about time for her to die". After dropping the phrase "it was about time for her to die" into a newspaper archive search, I was surprised to receive a hit from 1888 (the year of "Jack the Ripper"), bearing in mind that the Confession letter author appeared to mimic the language of a recent newspaper article on November 24th 1966, mentioning Cheri Jo Bates and invoking the name of "Jack the Ripper". The two phrases of "man is the most dangerous animal of all" and "it was about time for her to die", I could only find in newspaper articles dated 1932 and 1888 respectively, despite searching 331 years of newspaper archives.
So I refined the search to "Jack the Ripper" and "I am insane", hoping to find these two sections of text within one newspaper story. The search was successful, when I found several large articles in 1927 detailing the horrible mutilations of "Jack the Ripper", The newspapers stated "Nothing the London monster did exceeded the wanton devilishness the murders of half a dozen New York children by "rippers" whose crimes have stirred the city during the past fifteen years" (see below). This was a promising find, but I needed more.
The Confession letter of Swartz was fairly lengthy, but it was an additional piece of text he wrote on a soiled linen collar with a lead pencil, found in the lodging house near his body, that is of more interest. Although not of most importance, part of the message about the murder read "I felt sorry just two minutes after I did it". This reminded me of the phrase in the Riverside Confession letter where the author typed that he "followed her out after about two minutes". Although "just two minutes after" sounds similar to "after about two minutes", I'm not convinced that this was borrowed from the 1927 newspaper article about the murder of Julia Connors. However, just before Nathan Swartz wrote this section of text, he stated "I am guilty. I am insane", using five of the same words from the Riverside Confession letter, which read "I am not sick. I am insane".
CONNECTING RIVERSIDE TO THE ZODIAC USING JACK THE RIPPER [IN 6 PARTS]