This letter mailed to the San Francisco Chronicle is similar to the Vallejo Times-Herald and San Francisco Examiner letter and contained Part 3 of the three ciphers, which totaled up to become known as the 408 cipher, due to each part containing 136 characters.
The letters claimed credit for the first two attacks at Lake Herman Road on December 20th 1968 and Blue Rock Springs Park on July 4th 1969.
Betty Lou Jensen and David Faraday died in the Lake Herman attacks, but in the following encounter with the Zodiac at Blue Rock Springs, Michael Mageau survived despite being shot multiple times, unfortunately though Darlene Ferrin was not so lucky.
On August 8th 1969, just over a week after the arrival of the three letters, the 408 cipher was cracked by Donald Gene and Bettye June Harden of Salinas, California, who both used homophonic substitution to identify a solution.
The decoded cipher turned out to be the killer's thoughts and ramblings, containing numerous spelling errors, either by design or otherwise, but despite the letters claiming he would reveal his identity it turned out he was not so forthcoming. See also;
Vallejo Times Letter and Part 1 of Cipher
San Francisco Examiner and Part 2 of Cipher
I like killing people because it is so much fun it is more fun than killing wild game in the forrest because man is the most dangerous animal of all to kill something gives me the most thrilling experence it is even better than getting your rocks off with a girl the best part of it is that when I die I will be reborn in paradice and all the (people) I have killed will become my slaves I will not give you my name because you will try to slow down or stop my collecting of slaves for my afterlife ebeorietemethhpiti
This is the murderer of the 2 teenagers last Christmass at Lake Herman + the girl on the 4th of July near the golf course in Vallejo
To prove I killed them I shall state some facts which only I + the police know.
1 Brand name of ammo Super X
2 10 shots were fired
3 the boy was on his back with his feet to the car
4 the girl was on her right side feet to the west.
1 girl was wearing paterned slacks
2 The boy was also shot in the knee.
3 Brand name of ammo was western
Here is part of a cipher the other 2 parts of this cipher are being mailed to the editors of the Vallejo Times and SF Examiner. I want you to print this cipher on the front page of your paper. In this cipher is my idenity. If you do not print this cipher by the afternoon of Fry.1st of Aug 69, I will go on a kill ram-Page Fry. night. I will cruse around all weekend killing lone people in the night then move on to kill again, until I end up with a dozen people over the weekend.