The Zodiac case is fascinating for many reasons, but one oddity is that the killings don’t seem to be the most important part to the individual(s) behind these crimes. The main thing seems to be the communications. I am including a first batch of the known and suspected Zodiac letters with a bit of information about each. Look through them and see if there is anything that stands out. If you have questions, let me know.

Look at the handwriting. Does it match? Is it consistent from the beginning to the end of each letter? If it changes within a letter, how do you describe or explain that? Why does he misspell words? Can we get any clues about the person who wrote these letters?

Before going into the letters, I want to show you one item that belonged to one of the main suspects. It is the face of a watch. It has the word “Zodiac” and the symbol that the Zodiac used. But, there’s something else that we all missed. I believe that there is a strong clue in this photo which links the Zodiac killer to another set of murders called the Sonoma Coed Killings which occurred just after and a bit north of the Zodiac spree. See if you can figure out what I’m talking about.

Below is the first letter from the Zodiac once he/they started the series of crimes that we know of as the Zodiac killings. From July 1969.

The next one is the first letter using the name Zodiac. It is from August 1969.

This letter was written to an attorney on December 20, 1969.

The second part of this letter is below:

This is the 340 Cipher which has never been solved.

The “My Name Is” letter is broken into three parts here. Most people focus on these first two parts, thinking that a clue about the killer’s name is in the cipher. I think that there may be more important information in the third part.

Part 3 is all of the text after the13 symbol cipher.

This is the “Red Phantom” letter. It was from July 1974, and is assumed to be from the Zodiac. There is an interesting connection to one of the suspects, Rick Marshall. He ran an old movie theater that played a movie called “El Spectro Rojo” which roughly translates to “The Red Phantom.”

We will discuss the possibility that at least some of the communications use gematric coding, which is a way to substitute numbers for letters and then add them up. The added values give meaning to the letters. Some people believe that the key below was used by the Zodiac. Basically, you find the letter and then use the number below it.

There are two parts to the Halloween card from 1970. Do you see anything that might be a clue?

Finally, we have the SLA letter from February 1974 which may or may not be from the Zodiac. It is interesting that he mentions the Symbionese Liberation Army, which was a group that was responsible for some well known crimes. It seems that he was interested in other crime “groups.” It is also interesting that he mentions Norse language because some of his symbols may come from Norse runes.