This approach would be somewhat mimicked by the Zodiac Killer on July 31st 1969 (without the 1967 Bates letters currently published), who mailed three letters to the San Francisco Chronicle, San Francisco Examiner and Vallejo Times-Herald with his hidden cryptographic message of "the best part of it is that when I die I will be reborn in paradise and all the I have killed will become my slaves". One individual had already used the phrase "to die" in the Riverside Desktop Poem, Confession letters and Bates letters (six times), so looking at the transition from "she had to die" to "when I die" from Riverside to the Bay Area, it is certainly worth looking into further. Especially when you consider the fact that the Zodiac Killer never used the word "die" in any of his subsequent communications.
Also noteworthy, but not compelling, was the continuation in the religious overtones of "The Confession" letter and "She went to the slaughter like a lamb. She did not put up a struggle", to the message of the Zodiac Killer in the 408 cryptogram, in which he enciphered the wording "paradice", "reborn" and "afterlife" with respect to his death (when I die). The saying, "Like sheep to the slaughter", was used in respect to the notion of Jewish people being led passively to their deaths during the Holocaust. In other words, the suggestion that they offered no resistance or struggle - to be articulated by "The Confession" letter author when they typed "She (Bates) did not put up a struggle". and "She went very willingly". Cheri Jo Bates, it was claimed, was being marched passively to her death.
In Isaiah 53, a chapter in the Hebrew Bible tells of a virtuous servant who is murdered but does not protest: "Like a sheep being led to the slaughter or a lamb that is silent before her shearers, he did not open his mouth". The Confession letter author typed "I grabbed her around the neck with my hand over her mouth and my other hand with a small knife at her throat. She went very willingly". There appears a mix of religiosity with contemporary news in the Confession letter, but it still isn't compelling.