Why is the killer informing us he has killed seven people up to the end of October, when he has made this plainly obvious in the 'Dripping Pen' card by addition of the last entry as "Oct," meaning October. If the Zodiac Killer had murdered anybody in November, then surely the total would be 8 victims, with November added to the list of months. The killer further states "I though(t) you would nead a good laugh before you hear the bad news. You won't get the news for a while yet." But we didn't hear of any bad news before he mailed the Melvin Belli letter on December 20th 1969, or for months thereafter.
This may be because we had already heard the bad news, and the 'Dripping Pen' card was intended to be mailed slightly over a month earlier.
Mail can go astray from mailing to being postmarked, however, that avenue will not be explored here.
It seemed unusual for two such prominent communications to be sent either in tandem, or one day apart. The Zodiac Killer had obviously invested a lot of time crafting a new and innovative cipher, after becoming aware his first cipher had been cracked in a matter of days, and announced in the San Francisco Chronicle on August 9th 1969. So, after investing time and energy into his new masterpiece, it seemed strange he would take the shine and emphasis away from this new cipher, by tying it alongside the rather lengthy 'Bus Bomb' letter about the murder of Paul Stine on October 11th 1969 and his exploits in the park.
The 'Dripping Pen' card and cipher could have been mailed two weeks later to maximize impact. The context and choice of card, if chosen for purpose, also makes little sense. The message on the purchased greetings card read "Sorry I haven't written, but I just washed my pen." The Zodiac Killer, however, had written only 27 days earlier, when he mailed the October 13th 1969 Paul Stine letter containing the swatch of bloodied shirt. The supposed bad news we were supposed to get also never materialized, and in addition, he would repeat the month of October just one day later, reminding us of seven victims claimed, as if our attention span only lasted 24 hours. All these factors place this correspondence and its contents curiously out of place.
The wording "Sorry I haven't written, but I just washed my pen," if this card was chosen carefully, seems to imply the killer had not written to the newspapers for a while- longer than 27 days.
The Zodiac Killer prior to the October 13th 1969 Paul Stine letter, had not written to the newspapers since August 4th 1969, when the 'Debut of Zodiac' letter arrived at the San Francisco Examiner. That is over two months. It is longer regarding the San Francisco Chronicle, of over 10 weeks. This card now makes more sense. But why would the dripping pen (possibly red in color) be relevant to the Zodiac.
On September 27th 1969, Bryan Hartnell and Cecelia Shepard were enjoying a pleasant picnic at Lake Berryessa when a knife-wielding man approached wearing an theatrical executioner's costume, brutally stabbing the young couple 16 times in their back and abdomen. The assailant's hand or glove would have been covered in blood. Minutes later he wrote on the car door with a pen: Vallejo 12-20-68, 7-4-69, Sept 27-69 -6:30 by knife.
The pen would have been covered with blood. What better time to ironically proclaim in your next correspondence "Sorry I haven't written, but I just washed my pen," as if to imply he was the responsible for the callous attack and murder of Cecelia Shepard just days earlier, and was washing the blood from his pen. The author of the 'Dripping Pen' card further added "Could you print this new cipher in your frunt page? I get aufully lonely when I am ignored, so lonely I could do my Thing."
The Zodiac Killer, like most serial killers, don't have horns growing from their head- they go largely unnoticed and blend into society. The Zodiac Killer was certainly searching for notoriety, as opposed to the loneliness he experienced in everyday life. What better way, than to dress up in an executioner's costume and do his "thing."
The seventh victim was to become Paul Stine (or another taxicab driver) in San Francisco. He had already earmarked his next murder, and this was the "bad news" we were soon to receive. The addition of the month of October was the precursor to death, and unlike his previous attacks where he had to search out victims- in San Francisco they would literally come to him.
But why wasn't the 'Dripping Pen' card mailed after the Lake Berryessa attack?, assuming the communication didn't go astray from posting to postmark.
The Zodiac Killer likely had his ego dented after Donald Gene and Bettye June Harden cracked his 408 cipher in a matter of days. He may have began developing his more challenging cipher immediately in response, or at the very least sometime in August or September.
The Zodiac Killer chose the greetings card in respect to the Lake Berryessa stabbings, for which he could have then attached his cipher and mailed it. But something changed.
Did he want to revise or add to his cipher to incorporate the attack by the lake? Some have suggested the cipher may have been separated into two halves. Did the killer originally encipher a banal message, much like his original code, and wanted to completely redesign it. The intended murder at Presidio Heights was looming, and the killer was planning ahead. The cipher and card may have been placed on the back-burner.
On October 11th 1969, taxicab driver Paul Stine was murdered in Presidio Heights. The killer mailed a piece of the taxicab driver's shirt two days later, and followed up with more details on November 9th 1969 about his excursion into the park.
In between the October 13th 1969 Stine letter and November 9th 1969 'Bus Bomb' letter, the killer may have finalized his cipher, unable to replace the 'Dripping Pen' greeting card with an identical or relevant card, and with the Lake Berryessa attack cooling, mailed off both communications in unison. He stated we wouldn't "get the news for a while yet," totally negating the message he delivered one day later, that "I shall no longer announce to anyone when I committ my murders." Seemed like a quick change of heart. The card choice still made sense to him, if not us at this juncture, with the message inside now appearing chronologically repetitive in respect to the 'Bus Bomb' letter and the intended "bad news" had already occurred.