Six months after the Zodiac Killer's Albany, New York letter and code, another letter would arrive at the San Francisco Chronicle on January 30th 1974. Postmarked the day before (January 29th), this letter was a curious blend of The Exorcist movie (1973) and the comedic opera The Mikado (1885), two productions separated by 88 years.
The Zodiac Killer plagiarized The Mikado twice in the July 26th 1970 letter, but this appeared to have some purpose in relation to his hunting activities - that the Zodiac Killer had created a list of potential victims, who he would then kill and ultimately torture in paradise. This seemed at odds with his use of The Mikado in 1974. Any suggestion that the Zodiac Killer was contemplating suicide at this juncture because of his choice of Tit-Willow, appeared to be dashed in the following paragraph when he stated "If I do not see this note in your paper, I will do something nasty, which you know I'm capable of doing". The notion that the Zodiac Killer had reached a watershed moment and was about to ditch the pseudonym he had coveted for so many years, would also be premature, when he mailed the 1978, 1986 and 1987 letters, all containing his infamous introduction of "This is the Zodiac speaking".
The 1978 and 1987 letters had one thing in common with the 1974 letter, in that they all carried the wording "yours truly" or "yours truley", followed by a colon. This wording is commonly used before a signature, with the colon used to separate two independent clauses when the second explains or illustrates the first. In the 1978 and 1987 letters the Zodiac Killer follows "yours truly" with "guess", whereas, he inserts the plagiarized verse from Tit-Willow where his signature should be placed in the 1974 Exorcist letter. The primary conclusion to draw from this, is the Zodiac Killer was yet again asking us to "guess" his name through the verse of Tit-Willow.
He may have been bluffing, but giving us his first name in such cryptic fashion could never be realistically used as evidence against him, because any conclusions drawn from this verse through subjective interpretation, would never have any standing in a court of law. There are five things in relation to The Exorcist movie and the Tit-Willow verse that point to one name. There is also another that points backwards to the April 20th 1970 letter, when the Zodiac Killer teased us with his name by stating "My name is", followed by a thirteen character code. The Exorcist book was written by William Blatty in 1971, which told the story of a twelve-year-old girl possessed by a powerful demon, that was later adapted by director William Friedkin in the film version released on December 26th 1973. The Tit-Willow verse from The Mikado was created by William Schwenck Gilbert, which contained multiple examples of "Will" and "Bill" within words such as "Willo" and "Billowy" (Will and Bill being short for William). This verse followed The Exorcist introduction and the promise of a signature by use of "yours truley". If we look at the next paragraph in the Tit-Willow verse from the complete version, it reads "Now I feel just as sure as I'm sure that my name Isn't Willow, titwillow, titwillow". Very reminiscent of the "My name is" letter, but in this instance "My name Isn't".