I have been away from the Z case for several weeks as I have been handling some business in the real world.

I must say that the work done since my last post has been marvelous. A hearty round of applause for all involved.

My two cents: at this stage, I believe our best bet is to reach out to either someone who worked in the San Francsico area postal service during that time or the actual USPS today and simply ask.

I am also intrigued by the possibility that the machine number correlated to a dropoff location, meaning that mail collected from Mailbox XYZ was sorted into Machine 123. If that’s the case, there might be hope for identifying dropoff locations.

Still, we need to speak with someone currently or formerly in the Postal Service. I will try to see if I can speak with anyone who might have knowledge of this.

FWIW, I tried to find the contact information for the current Postmaster for the San Fran area and completely hit a dead end. No address or number for any office related to them.

I don’t know what to say about the military thing except that I don’t see him (the Zodiac) as a military man. I do recognize that there are some characteristics or signs of the possibility. With that being said I found a list of military zips and shortened it down to only those that deal with the San Francisco sectional center or whatever it’s called.

The list for anyone interested:

96202,APO,AP
96204,APO,AP
96205,APO,AP
96206,A P O San Francisco,AP
96207,APO,AP
96208,APO San Francisco,AP
96212,APO San Francisco,AP
96213,A P O San Francisco,AP
96214,APO San Francisco,AP
96218,APO,AP
96224,A P O San Francisco,AP
96230,A P O San Francisco,AP
96239,A P O San Francisco,AP
96248,APO San Francisco,AP
96251,A P O San Francisco,AP
96257,APO,AP
96258,APO,AP
96260,APO,AP
96264,A P O S F,AP
96266,APO,AP
96271,A P O San Francisco,AP
96274,APO San Francisco,AP
96278,APO,AP
96286,A P O San Francisco,AP
96293,A P O San Francisco,AP
96301,A P O San Francisco,AP
96305,A P O San Francisco,AP
96306,FPO,AP
96310,Bremerton,AP
96311,A P O San Francisco,AP
96319,APO,AP
96322,FPO,AP
96324,A P O San Francisco,AP
96326,APO,AP
96328,A P O San Francisco,AP
96331,A P O San Francisco,AP
96334,A P O San Francisco,AP
96335,APO San Francisco,AP
96336,APO,AP
96337,APO,AP
96338,APO,AP
96343,A P O San Francisco,AP
96348,FPO,AP
96349,FPO,AP
96351,FPO,AP
96358,A P O San Francisco,AP
96362,FPO,AP
96366,A P O San Francisco,AP
96367,A P O S F,AP
96368,APO,AP
96369,APO San Francisco,AP
96370,FPO,AP
96372,FPO,AP
96373,FPO,AP
96374,APO,AP
96375,FPO,AP
96376,APO,AP
96377,FPO,AP
96379,FPO,AP
96384,APO,AP
96386,APO,AP
96408,A P O San Francisco,AP
96432,APO San Francisco,AP
96455,A P O San Francisco,AP
96460,APO San Francisco,AP
96461,APO San Francisco,AP
96515,FPO,AP
96519,A P O San Francisco,AP
96520,DPO,AP
96524,A P O San Francisco,AP
96528,APO San Francisco,AP
96534,FPO,AP
96538,FPO,APl
96542,APO,AP
96543,APO,AP
96546,APO,AP
96548,APO,AP
96549,APO,AP
96551,APO,AP
96553,aPO,AP
96554,APO,AP
96555,A P O San Francisco,AP
96595,FPO,AP
96601,F P O,AP
96602,F P O,AP
96603,F P O San Francisco,AP
96604,F P O San Francisco,AP
96606,FPO,AP
96607,FPO,AP
96608,FPO San Francisco,AP
96609,FPO,AP
96610,FPO San Francisco,AP
96612,FPO,AP
96614,FPO San Francisco,AP
96618,F P O San Francisco,AP
96621,F P O San Francisco,AP
96622,FPO,AP
96623,F P O San Francisco,AP
96624,FPO San Francisco,AP
96627,F P O San Francisco,AP
96628,F P O San Francisco,AP
96629,F P O San Francisco,AP
96630,F P O San Francisco,AP
96631,F P O San Francisco,AP
96632,FPO San Francisco,AP
96633,FPO San Francisco,AP
96635,F P O San Francisco,AP
96636,A P O San Francisco,AP
96637,F P O San Francisco,AP
96639,F P O San Francisco,AP
96641,F P O San Francisco,AP
96644,F P O San Francisco,AP
96646,F P O San Francisco,AP
96647,FPO San Francisco,AP
96648,F P O San Francisco,AP
96649,FPO San Francisco,AP
96651,F P O San Francisco,AP
96654,F P O San Francisco,AP
96656,FPO San Francisco,AP
96660,F P O San Francisco,AP
96661,F P O San Francisco,AP
96663,F P O San Francisco,AP
96664,FPO San Francisco,AP
96665,F P O San Francisco,AP
96666,F P O San Francisco,AP
96667,F P O,AP
96669,F P O San Francisco,AP
96671,F P O San Francisco,AP
96672,F P O San Francisco,AP
96673,F P O San Francisco,AP
96674,F P O San Francisco,AP
96675,F P O San Francisco,AP
96677,F P O San Francisco,AP
96678,F P O San Francisco,AP
96679,F P O San Francisco,AP
96680,F P O San Francisco,AP
96683,F P O San Francisco,AP
96685,F P O San Francisco,AP
96688,F P O San Francisco,AP

Soze

I have an idea on how we can possibly get around the whole mailbox thing. Its using the sectional center, the city postmark on each envelope and the zodiac’s own words. We need a listing of everything the zodiac ever said or did that could be thought of as postal related. Maps or visuals I believe are needed. Knowing precisely where the sectional center I don’t believe is necessary given all possible locations are very close to one another.

Soze

The idea (limited. Going off top of head. More examples needed)

July 31, 1969. Mails a letter to Vallejo with SF post mark. Up until lately we have thought he mailed it from SF but now recognize it could have been mailed from another location outside of SF. Some people have thought previously that the Zodiac was ignorant to postage or ignorant to how much postage was necessary to mail from SF to Vallejo. It would seem he might not have been so ignorant after all given that he may not have mailed from SF to begin with. So it would seem, postage wise, the Zodiac was trying to mail a letter from some distance away. How much of a distance?

I posted a map a few pages back. Created it in 2011, in the infancy stage of studying post offices, and don’t know if I have covered everything in terms of the San Francisco sectional. So it may need updating. We also need one for santa Clara and what was that other county? Well one for it too.

Well the map I show shows the coverage to be around Sunnyvale. Don’t have the numbers available but it’s clearly a good distance. How much of a distance? Enough to think 4 stamps was necessary? Not in my present day mindset but who knows. Maybe he thought it was. Are there specifications, postal wise, that suggest one stamp is good for this length of travel, 2 for this length and so on?

Just outside that coverage area is another sectional center. There is presently 17 in that state. The guy could have lived as little as a quarter mile outside that coverage area, in another coverage area, and drove that quarter mile to mail a letter so that it would have a completely different city of origin.

Later we see envelope after envelope about airmail. Zodiac have a fascination with planes? He did talk about airplane cement. Sorry. Trying to be funny here. Anyway, he says airmail? Why? To us ignorant of the post office, who have to dig and dig for information, the inclusion of airmail is strange when we think the location of mailing is in SF. Airmail isn’t necessary. To zodiac, who may not have lived in or mailed from the SF area, perhaps not so much. Perhaps he knew it had to travel a good distance via airmail. Airmail involves mail traveling equal to or greater than 200 miles.

Then there is the point of using the entire portion of a stamp book. My memory says that the stamp talked about mailing early. Or something about the envelope said mail early. Mailing early ensures a speedy delivery. Speedy delivery for a particular day? A particular time of day? Maybe distance might be the reason we have a pm postmark if they mailed early in the day? It had to travel a good distance to receive a pm postmark.

There are other things I’m sure, like the Phillips 66 map, that point to PO.

So what could we have so far? He could have lived as far south as Sunnyvale on the short side. Factor in airmail and he could have lived as far south as San Louis Obispo. So, geographically speaking, could it be that he lived between Sunnyvale and San Louis Obispo? San Louis Obispo is exactly the same distance away from Los Angeles as it is San Francisco. He used airmail on the Los Angeles letter envelope as well.

Is there more that can be gleemed? Could we narrow it down further using other statements or other envelopes? I’m optimistic.

Soze

It would have cost the same 6 cents per ounce to mail a letter to Vallejo though, regardless of the drop-off location.

One thing jumps out:

Could the letters have been mailed from Mare Island?

Zip prefix 966 would theoretically fit the bill.

940: San Mateo & Santa Clara Counties
941: San Francisco
943: San Mateo & Santa Clara Counties
944: San Mateo County
962: US Military Bases in Korea
963: US Military Bases in Japan
964: US Military Bases in the Philippines
965: US Military Bases in the Pacific & Antarctic
966: US Military Bases, Naval/Marine

I don’t know what to say about the military thing except that I don’t see him (the Zodiac) as a military man.

Again, it certainly wasn’t the case that I was wanting to present evidence that Zodiac might be military. I was merely demonstrating that the evidence points to the ‘Postal Concentration Center’ at Main Street having been an operation for processing military mail and so, as such, cannot be the USPOD ‘Sectional Center Facility’ that we are looking for.

Knowing precisely where the sectional center I don’t believe is necessary given all possible locations are very close to one another.

I don’t know if anyone picked up on the potential inference from what I found in the Post Offices Directory, or whether you think it is worth thinking about any further.

To post the relevant image again:

and the associated text (with added emphasis):

Listed below are the sectional centers [bold] in alphabetical sequence by State showing the first three numbers of all ZIP Codes to be routed through these sectional centers.

The three-digit codes shown in italics are those of multicoded cities having their own three-digit identification and are not considered sectional centers.

Isn’t it the case that this seems to be saying that the SCF for San Francisco is not in 941, 943 or 944, but in 940? Which, without having done the full research yet, would look like it puts it in South San Francisco or San Mateo County?

I’m not convinced by this idea, for sure. But it’s probably worth exploring a little further to check out.

No, I’m not interpreting it that way.

Are there specifications, postal wise, that suggest one stamp is good for this length of travel, 2 for this length and so on?

Pricing was done on a ‘zone’ basis. (note: not the same meaning for ‘zone’ as we got caught up in previously; completely different.)

This, again, from the 1969 Post Offices Directory:

However, this is easy to interpret in the case of the letters that were mailed to San Francisco addresses. Having been processed through the SF Sectional Centre to SF destinations, these would all have been ‘local’ zone.

We can certainly look at it more closely, but I would tend to think that the overpostage was merely to draw attention to the envelope, and get it to stand out once it arrived at its destination.

If not, then who are we looking at? Someone who could construct a sophisticated cipher that has beaten all attempts to break at after 50 years, but who doesn’t understand postage rates?

No, I’m not interpreting it that way.

That’s good enough for me!

One thing jumps out:

Could the letters have been mailed from Mare Island?

Zip prefix 966 would theoretically fit the bill.

…

966: US Military Bases, Naval/Marine

I am, personally, quite drawn to this idea as a possibility. If at all feasible, it would potentially tie up a number of loose ends. Not least, it would go some way to explaining the evident (from GeoProfiling) familiarity with the Vallejo area, but at the same time not require regular trips into San Francisco to send letters.

The only thought I have at this point in time against this idea – and it is potentially a big one – is that the mail would have to have been processed first through the Navy mail system, even if only minimally, and the envelopes were marked so distinctively that they would surely (after the first few) have been intercepted at source.

It would have cost the same 6 cents per ounce to mail a letter to Vallejo though, regardless of the drop-off location.

Agree. The postage rate to any location, if I understand it correctly, is calculated by zoning based on the ZIP of the source Sectional Center against that of the destination Sectional Center. So, therefore, it wouldn’t matter where a letter (to any destination) was posted within the region covered by the San Franscisco SCF, it would still require the same postage.

Here is a reddit thread that adds context to the letter/number issue:

https://www.reddit.com/r/philately/comm … _postmark/

Here’s a quote (emphasis mine):

"Short answer: This is a service mark."

"This is a machine cancel. Almost all machine cancels have what is called a service mark. It identifies which machine/operator processed the cancellations and processing of the mail item. It is actually unusual to see a service number that includes a letter. Larger post offices can have many different machines/operators. Sometimes 30+"

"Imagine a line of cubicles in an office only instead of cubicles is a series of mail processing stations, each with its own machine cancelling device within a single post office. The service marks indicate which cubicle or in this circumstance which processing station did the work."

So, as others have said, the letter/number on the Zodiac postmarks are service marks that merely indicate by which machine inside the post office the letter was cancelled. I suspect the reason these numbers also have letters is because they were processed at a very large post office with many machines.

Shaq, I believe the zone chart you posted applies to parcels (packages). I’m quite sure in 1969 that a letter mailed anywhere in the US cost the same.

(A letter mailed from Vallejo to Vallejo would cost the same as a letter mailed from Vallejo to New York City.)