If you run the message from the face of the 'Dripping Pen' card to inner, it reads "Sorry I haven't written, but I just washed my pen and I can't do a thing with it". So when the Zodiac Killer wrote "I get aufully lonely when I am ignored, so lonely I could do my Thing", he was indicating that in the future when he needed some attention he would write again. His Thing being his propensity to put pen to paper, or in the case of Lake Berryessa, to metal. He was effectively addressing the police when he wrote "I though you would need a good laugh before you hear the bad news. You won't get the news for a while yet". In fact, the bad news would arrive in exactly thirteen days time - and it was directed towards the police in regards to the month of August. In effect, his next correspondence would be pushing the same narrative as the car door and greetings card, of his involvement in the deaths of Deborah Furlong and Kathy Snoozy.
On November 21st 1969, a letter arrived at the San Jose Police Department addressed to a particular law enforcement officer. The letter was threatening a widow - so much so - that police initiated 24-hour surveillance on the woman's home. The police stated that "they believed the widow in the message may be Mrs......" In other words, the woman wasn't directly named in the correspondence, but they had by reasonable deduction concluded who the threat was aimed at. I believe that the Zodiac Killer in his continued drive to cement the notion of his involvement in the two teenage girls murders, mailed this "bad news" to the San Jose Police Department. Can it really be a coincidence that he wrote "by knife" on the car door to plant the seed, added the "Aug" on the 'Dripping Pen' card, then mailed his next correspondence to the City of San Jose? In addition, this new communication began with some familiar words: "There's no doubt I will do my Thing".
I have no doubt the Zodiac Killer was scouring the newspapers about this crime - so imagine he came across such a headline:
"An elderly widow, Maureen Jones, was today helping police with their investigation into the senseless murders of two young girls in San Jose, Sergeant Johnston said", or "An elderly widow, residing at Seacreek Way, was today helping police with their investigation into the senseless murders of two young girls in San Jose, Sergeant Johnston said". These article excerpts are fictitious, designed to show what Zodiac may have read in any number of articles I have no access to.
The Zodiac Killer never mentioned his victims by name, so it is entirely plausible that whether he knew this woman's name or not, he could, by sending a threatening letter to police using the term "widow", and addressing the communication to "Sergeant Johnston", convince police that the threat was a credible one. This may be why the police believed they knew who the woman was, despite the fact her name was never mentioned in the correspondence mailed to the San Jose Police Department. Because she had recently received newspaper coverage.
-- + 6 2 + --, containing two dashes either side, two pluses, and the numbers 6 and 2. The idea that anybody looking at this code could arrive at 1620 without having previous reason to suspect this four number solution, seems unlikely. But if investigators knew that "Maureen Jones" lived at a residence, such as 1620 Seacreek Way, San Jose, then they might have reason to believe this is what the code was implying. Earlier newspaper reports stated "A killer armed with a thin-bladed stiletto was hunted here today as the one who savagely stabbed to death two teenage girls yesterday as they picknicked in Almaden Valley. The scene where the bodies were found is just south of Blossom Hill Road, two blocks west of Calahan in the northern end of the valley. About 10:00 am yesterday, the girls packed a lunch and left Deborah's parents' San Jose home for a picnic atop a grassy knoll nearby. The picnic ground is a rugged area, near a narrow, serpentine trail used by motorcyclists for hill-climbing contests". So, if we could find a 1620 residence in San Jose, possibly close to the crime scene, this may be the location of the "widow" Zodiac was targeting.
As shown above, in the October 1st 1969 San Francisco Examiner article "San Jose police, to the south, inquired of law enforcement officers here whether there was indication that the "Cipher Killer" might be linked to the knife slaying of two teenage girls Aug.3". Therefore, would it really be that surprising if the Zodiac Killer had capitalized on their suspicions and mailed a threat to the San Jose Police Department? He knew he would be taken seriously by police - and why they were prepared to instigate 24-hour surveillance on the residence of the "widow" mentioned in the letter.