13TH VICTIM CLAIMED AND "FK IM CRACKPROOF"

Out of curiosity I looked through archived newspapers for the word "Crackproof" to see what context it might have been used in around the 1969-70 time period. The only context I could find where it was used was in ads for goods such as dishes, garbage cans and garden hose. It was usually written as two words, crack proof, but sometimes it was hyphenated, crack-proof. I could not find the word in the text of an article but my choice of newspapers to go through was limited to many smaller newspapers and the SF Chronicle was not one of those newspapers. FWIW

I wonder about more specialised publications. I wonder what those would have been back then if there were any. 'Annoying ciphers to the police monthly'?

EDIT: Possibly not

The Codebreakers – The Story of Secret Writing (ISBN 0-684-83130-9) is a book by David Kahn, published in 1967 comprehensively chronicling the history of cryptography from ancient Egypt to the time of its writing. The United States government attempted to have the book altered before publication, and succeeded in part.
[edit]Overview

Bradford Hardie III, An American Cryptographer during World War II, contributed insider information, German translations from original documents, as well as intimate real-time operational explanations to The Codebreakers.
It is widely regarded as the best account of the history of cryptography up to its publication. William Crowell, former deputy director of the National Security Agency, was quoted in Newsday as saying "Before he (Kahn) came along, the best you could do was buy an explanatory book that usually was too technical and terribly dull."

Interesting note
Because of the year of its publication, the book did not cover most of the history concerning the breaking of the German Enigma machine (which became public knowledge only in the 1970s)

Z composed the word crackproof out of separate words crack and proof so could have come from many sources.

I do wonder if there would be anything to gain by analyse the glue used, however this was probably already done to the Halloween card.

Yes, I could see that Zodiac's "crackproof" was made from two different kinds of type. I guess that makes it another instance of mispelling on his part! I also did a google news search of the words and didn't come up with anything different than what I found by going through the newspaper archives. I kind of thought I'd find crack proof in reference to safes but didn't. Using "crack proof" in a web google search just yielded a bunch of hits for computer related stuff for the most part.

Looks to me like some of the words used came from an off-white paper source, like a newspaper, and some have an indiscernible outline, possibly from a source with true white paper, a magazine or book perhaps.

Probably been spotted before but just in-case. I have flipped the image and highlighted the area in question. You are looking for what appears to a very faded stamp with title/line then another title and a few more lines with something written on one of the lines.

So is that the flip side of the card?

If you do a google or yahoo search for "code" "cipher" and "crack" you get a lot of results.

The term "crack" was often used in relation to codes. I think this is how Zodiac meant the term "crackproof">

http://www.eiaonline.com/history/codecrackers.htm

Traveller I have not seen those lines on the postcard before. I don't think that they have anything to do with the postmark but might be from how the postcard was stored. Maybe there was another piece of paper on top of the postcard and the printing on that bled onto the card???

Yes, AK, if you do a search for those words individually you can get any number of hits. I was specifically looking for "crackproof" or "crack proof" to try to determine if Zodiac may have been inspired by something in particular around the time he sent the card. I didn't find anything. Zodiac certainly was inspired by some words that were current at the time, like Blue Meanies and Pigs.

The word "crack" can be used in reference to codes and ciphers but also in reference to safes. Nowadays it's something that will get you high!

Nice find Trav. Probably just his real name and address, transferred from some other document as Seagull suggests.

The use of crackproof on this card, if one assumes refers to ciphers, implies that if his ciphers were solved they would close in on him...

I noticed the lines first and actually thought I saw the telltale 'f' so decided to enhance it. It's not the flipside AK I just flipped it because the impression appeared to be in reverse - as Seagull says, probably transferred from something that was on top of the card.

OR...it could be an evidence stamp on the reverse of the card bleeding through? Hard to say as I don't know how thick or thin the card was.

OR as Bentley suggests it's just his full name and address, probably from a check he messed up and used it to construct the message - in which case not important lol.

The other side of the card is in the zkf.com gallery in case anyone hasn't seen it.

Cool, must have a look.

In the meantime here's the image not flipped and I've also spotted an '8'. Also marked an area below the main imprint but it's prob nothing, just discolouration.

Those areas you've bracketed almost look like they have been erased, leading to the lighter coloring.

Looks like as of May 1, 1971, LE and Paul Avery believed it a fake:



http://www.zodiackiller.com/AveryReport1.html

Sorry if this has already been discussed in this thread, I only had a quick proof read over the posts and couldn't see it mentioned so, here goes...





I was not aware of this, but, according to the book 'This is the Zodiac Speaking: Into the Mind of A Serial Killer', Michael Kelleher writes the following.

"Beneath the 13 was a cross drawn in human blood and a P.S pasted upside down on the left side of the card"

Assuming that this statement by Kelleher is correct, and the cross on the card was written in human blood, then I have a question. Obviously, back in 1970, blood typing was available so I assume this is how they know the blood was of human origin. But DNA was still decades away and has only recently became available to science. Has the blood on this card been tested and a DNA profile extracted?

Welsh Chappie wrote:

Sorry if this has already been discussed in this thread, I only had a quick proof read over the posts and couldn't see it mentioned so, here goes...





I was not aware of this, but, according to the book 'This is the Zodiac Speaking: Into the Mind of A Serial Killer', Michael Kelleher writes the following.

"Beneath the 13 was a cross drawn in human blood and a P.S pasted upside down on the left side of the card"

Assuming that this statement by Kelleher is correct, and the cross on the card was written in human blood, then I have a question. Obviously, back in 1970, blood typing was available so I assume this is how they know the blood was of human origin. But DNA was still decades away and has only recently became available to science. Has the blood on this card been tested and a DNA profile extracted?

It is not blood,it was thin red coloured paper pasted onto the card