A brief reminder before we begin. Phil Sins and Paul Avery concluded the mailing of the Halloween card was a hidden reference to Bates.

Faraday and Jensen, Dec 20th. -> Melvin Belli letter Dec 20th (one year to the day).

Mageau and Ferrin, July 4th. -> August 4th, SF Examiner letter (one month to the day).

Hartnell and Shepard, Sep 27th -> October 27th, Paul Avery Halloween card (one month to the day + possible Bates reference).

Bates, Oct 30th -> April 30th Bates had to Die letters (6 months to the day)

Let’s say for a moment this serial killer who remembers and writes dates on a target’s car door is actually doing this and it’s not just coincidence.

This means the Zodiac was already working to this anniversary theme before Paul Avery published the Bates connection which the Zodiac appeared to sign off on.

A theme the writer of the Bates had to Die letters seems to have also engaged in.

It’s not inconceivable that this is all coincidence except the Zodiac is the confounding variable because he is the sort of character who would be into things like this. The problem is that other offenders can come up with these anniversary ideas independently. Seems it’s part of their whole totem phase. To find ways to rekindle the emotional need.

Still then there is all the other stuff pointing at a connection between Bates and the Zodiac. I find it compelling or this guy was very familiar with the case down to the fact he picked up on the anniversary connection.

Anyway seems Zodiac was doing it before Avery revealed the Bates connection which has this same thing going on.