More conventional reasons to favor San Francisco:

1) When Zodiac writes the font of address on the envelope imitates the font of the numerals on the wall of the home. This implies Zodiac had been to the house.
2) The Belli letter isn’t double-postage-d, implying confidence it would get there.
3) The Ray Davis killing suggests San Francisco in a roundabout way: The body of Ray Davis was found not far from the mayor’s neighborhood. So was Paul Stine’s. If that is intentional, then it means Zodiac knew where the mayor of SF lived.
4) The references to nice buttons that people are wearing "around town." Clearly that’s San Francisco and not Vallejo.
5) The opera-loving, Joyce-quoting Zodiac seems like a better fit in San Francisco than Vallejo.

PS: I’m open to either location. Heck, I’m open to LA. Or Cincinnati.

It makes sense that he would live in San Francisco like Jack the Ripper lived in London. An everyman who blended into the background.

The opera-loving, Joyce-quoting Zodiac seems like a better fit in San Francisco than Vallejo.

There’s no reason to believe the Zodiac was an opera fan.

The "little list" song was used to sell soap. It could have simply been a tune that got stuck in his head.

I think Rossmo might be wrong in this case. Obviously he’s an expert and I’m not. Still …..

Geographic profiling is about probabilities (not certainties). Yet, like any form of statistical analysis it can provide insight, although even then the findings are subject to interpretation. As such, this sort of profiling is age old, and not too different to what amateur sleuths attempt to do on the forums (expertise comes in many forms). However, Rossmo has literally invented algorithms to assist detectives in convicting killers.

Rossmo’s analysis is conventional. I don’t mean that in a bad sense, since conventional is right more often than not. But his framework is that Zodiac lived near Vallejo, went hunting in the surrounding areas, until he was ready to strike, etc. Then he spreads his activity outward from there.

Yeah, I agree he’s fairly conventional in his baseline assumptions, and honestly states that at the beginning of his paper. You say conventional, I say sensible and rational. He also explains why you simply can’t add extraneous murders to the dataset, without distorting the analysis. I don’t think he’s conclusion-fitting, yet as you point out perhaps not without bias. I do however, think he has looked at the evidence in sufficient detail and I like that he picks up geographical mentions in Zodiac’s communications (there’s lots of mentions of Vallejo, naturally).

If you use the Holes logic in this case …. if you drive on 101 across the Golden Gate Bridge, eventually it forks into Highway 37 that goes through Vallejo, Then 37 stops being a highway and turns into Columbus Parkway just a little ways up the road from Blue Rock Springs Park. Beyond that, it’s a short drive with only 1 turn to the Lake Herman Road site. Meanwhile, in the Stine murder, the killer goes deep into neighborhood. The Holes logic makes a lot of sense here, and points to LHR and BRS being commuter killings, while Stine is deeper in a familiar neighbourhood.

To my untrained eye, the Rossmo heat-map looks like it highlights the major roads and highways that the killer frequents, rather than identifying his home. As I understand it, organised murderers rarely kill right next to their home. Zodiac is very car-based and that is built into his MO. I’m always amazed how Vallejo seems a crossroads for so many locations.

Interestingly, Rossmo was originally a police officer himself and his personal bio provides testimony to his powers of analysis.

In 1995, he was promoted to detective inspector and founded a geographic profiling section within the Vancouver Police Department. In 1998, his analysis of cases of missing sex trade workers determined that a serial killer was at work, a conclusion ultimately vindicated by the arrest and conviction of Robert Pickton in 2002. A retired Vancouver police staff sergeant has claimed that animosity toward Rossmo delayed the arrest of Pickton, leaving him free to carry out additional murders.[3] His analytic results were not accepted at the time and after a dispute with senior members of the department he left in 2001. His unsuccessful lawsuit against the Vancouver Police Board for wrongful dismissal exposed considerable apparent dysfunction within that department.

More conventional reasons to favor San Francisco:

1) When Zodiac writes the font of address on the envelope imitates the font of the numerals on the wall of the home. This implies Zodiac had been to the house.
2) The Belli letter isn’t double-postage-d, implying confidence it would get there.
3) The Ray Davis killing suggests San Francisco in a roundabout way: The body of Ray Davis was found not far from the mayor’s neighborhood. So was Paul Stine’s. If that is intentional, then it means Zodiac knew where the mayor of SF lived.
4) The references to nice buttons that people are wearing "around town." Clearly that’s San Francisco and not Vallejo.
5) The opera-loving, Joyce-quoting Zodiac seems like a better fit in San Francisco than Vallejo.

PS: I’m open to either location. Heck, I’m open to LA. Or Cincinnati.

Where does Zodiac quote James Joyce?

Where does Zodiac quote James Joyce?

Good question.

There was a bunch of discussion about Joyce in the Manalli forum:
https://zodiackillersite.com/viewtopic.php?f=46&t=363

Geo-profiling is a tool in the box. It’s less effective with organized killers. The profiles I saw for GSK completely missed Citrus Heights, so I wouldn’t pitch a tent around those "red zones."

I mean, there’s other possibilities. Maybe he lived in Oakland or San Mateo, worked in SF, and had family in Vallejo (hence killings around the holidays).

There was a bunch of discussion about Joyce in the Manalli forum:
https://zodiackillersite.com/viewtopic.php?f=46&t=363

Right but none of that is Zodiac actually quoting James Joyce.

James Joyce?

"Possible James Joyce referencing" doesn’t have the same ring to it.

Has anybody ever wondered why despite two Vallejo attacks and a Vallejo phone he call not one of the letters was sent from Vallejo ?

Just my theory, he is attacking close to home in Vallejo, and working weekdays in SF mailing the letters from there.

Has anybody ever wondered why despite two Vallejo attacks and a Vallejo phone he call not one of the letters was sent from Vallejo ?

Just my theory, he is attacking close to home in Vallejo, and working weekdays in SF mailing the letters from there.

I saw that Cragle posted this the in past, it does seem that the mailings are mainly in the North end of SF around the bridge exits.

I don’t know if there was a lag between the mailings and being postmarked (and why they are recorded as Mon & Tues).

This was a project we did a deep dive in over a year ago. If you read through to the end of the thread, you will see that map is debunked. There is no correlation between the numbers on the postmarks and the location from which they were mailed.

The map is worthless. It’s a dead end.

This was a project we did a deep dive in over a year ago. If you read through to the end of the thread, you will see that map is debunked. There is no correlation between the numbers on the postmarks and the location from which they were mailed.

The map is worthless. It’s a dead end.

Yep it was Rabbit hole that a few of us including Chaucer spent far too much time investigating unfortunately.

I’ll take a full read of the thread, thanks anyway. It’s an interesting topic.