Here we will revisit an article published by the San Francisco Examiner on October 22nd 1969, in which Professor D.C.B. Marsh, president of the American Cryptogram Association laid down a challenge to Zodiac. The words he chose to use in this article may be the bedrock to much of the subsequent Zodiac communications, beginning with the 340 cipher, mailed only seventeen days after the San Francisco Examiner article. Here are the crucial extracts from that article.
'Dr Marsh told the Examiner today: "The killer wouldn't dare, as he claimed in letters to the newspapers, to reveal his name in the cipher to established cryptogram experts. He knows, to quote Edgar Allen Poe, that any cipher created by man can be solved by man. Zodiac has not told the truth in his cipher messages to the Examiner, the Chronicle and the Vallejo Times-Herald. Zodiac has not done this, because to tell the complete truth in relation to his name-in cipher code-would lead to his capture. I invite Zodiac to send The American Cryptogram Association a cipher code, which will truly and honestly include his name." It is difficult to believe that Zodiac, an avid reader of the newspapers, could resist such a challenge, particularly as he had promised to reveal his identity in the 408 cipher two months earlier, but failed to do so.  

The key section to note in the challenge by Professor D.C.B. Marsh is: "I invite Zodiac to send The American Cryptogram Association a cipher code, which will truly and honestly include his name."
Seventeen days later, the Zodiac Killer duly obliged with the November 8th 1969 340 cipher. Could this cipher have included the killer's name, but not in the format envisaged by Professor D.C.B. Marsh?
In a previous article entitled 'Zodiac Admitted 340 Not a Real Cipher' we examined the idea that the 340 cipher was inextricably linked to the Zodiac's 'Halloween' card, mailed on October 27th 1970. One can notice that the word "By" is located in each of the four quadrants of the 340 cipher. The author of the cipher also placed the letters F and K adjacent to one another no less than seven times (situated in each quadrant). But of particular interest was the corrected section on the sixth line of the 340 cipher, where the author chose to scrub out a forward facing K and replace it with a backwards K, elevated above the blacked out section.
The Zodiac Killer was known for numerous spelling errors in his communications, so why was it seemingly imperative to correct this one mistake? Was this correction crucial to the interpretation of the cipher, or was he drawing our attention to the letters in this section of the cipher? Are the F and K characters the initials of the Zodiac Killer?
This observation carries little merit on its own, so to bolster any argument for the initials of the Zodiac Killer being present in the 340 cipher, we have to explore the rest of his communications, particularly from around the time of the 'Halloween' card, in which we suggested was his admission that the 340 was unfortunately "no cipher". 
Linking the 'Halloween' card and 340 cipher through a Tim Holt comic book and explaining to us that the solution was "sorry no cipher." left us with the possibility that the 340 cipher was just a collection of puzzles, in which may have contained his name. The Zodiac Killer "wouldn't dare, as he claimed in letters to the newspapers, to reveal his name in the cipher to established cryptogram experts", but he may have given us the abridged version.
We now enter the crucial phase of Zodiac communications, from the '13 Hole' postcard mailed on October 5th 1970, to the 'Exorcist' letter mailed on January 29th 1974. This critical period of four consecutive communications, is probably key to understanding the message the Zodiac Killer was trying to push. That the 340 was "sorry no cipher."      

In the '13 Hole' postcard the Zodiac Killer stated "There are reports city police pig cops are closeing in on me. Fk I'm crackproof. What is the price tag now?"
This section of pasted letters was placed upside down. The question one should be asking is 'what is the purpose behind this'. If its significance had no relevance to the actual postcard, did it have relevance to another communication.
The wording "FK I'm crackproof" could indicate that the killer thought he was immune from capture, however, it could also be a reference to his 340 cipher once again. The word "crackproof" is something that is unable to be cracked.
The 340 cipher would certainly be impervious to cracking, and certainly resistant to the attempts of The American Cryptogram Association had the killer devised a cipher not of conventional understanding, of which Professor D.C.B. Marsh was hoping when he laid down the challenge. The F and K text being flipped on the '13 Hole' postcard reminds one of the flipped K (next to F) on the only corrected portion of the 340 cipher. If FK were the Zodiac Killer's initials, then he certainly could be declaring that he was crackproof. 
​Professor D.C.B. Marsh stated  "He knows, to quote Edgar Allen Poe, that any cipher created by man can be solved by man. Zodiac has not told the truth in his cipher messages to the Examiner, the Chronicle and the Vallejo Times-Herald. Zodiac has not done this, because to tell the complete truth in relation to his name-in cipher code-would lead to his capture." However, the Zodiac Killer could give his name in the form of initials without any fear of revealing his identity, and without risking his immediate capture. This may have manifested itself when he mailed his following cipher on April 20th 1970, when he opened with the gambit "This is the Zodiac speaking. By the way have you cracked the last cipher I sent you. My name is...."  The code placed underneath was likely an immediate rebuttal to this question. 

All he is probably doing, is stating "My name is FK," and once again telling us he is crackproof, just like the '13 Hole' postcard, which would be mailed five and a half months later. The phrase "FK I'm crackproof" fits perfectly in circular formation within the '13 Symbol' cipher- which itself contains a series of circled 8's. Structured in this fashion, the F and K yet again align, as does the K and M in both the cipher and phrase. 
Continuing with our four consecutive communications from October 5th 1970 onward, we now have the October 27th 1970 'Halloween' card promising to yet again reveal his name: "I feel it in my bones, You ache to know my name, And so I'll clue you in." Again we feel disappointed only to see the word "Boo" on the card inner- but we know the Zodiac Killer isn't going to make this a conventional and straightforward offering. He offers us the phrase "sorry no cipher," but can we find his name or initials within this communication. This is where it gets more difficult, nevertheless, we are aware that within the '13 Hole' postcard he reversed or flipped the text containing "FK I'm crackproof" and he flipped the K (next to the F) on the sixth line of the 340 cipher. So the obvious conclusion, is to look for flipped or reversed text within the 'Halloween' card.  

The only place that F and K exist within one word on the 'Halloween' card, is in the word "knife." either side of the reversed letter N.
If we flipped the reversed N back to its appropriate position, the F and K of "knife" would be reversed yet again.
Now let us turn our attention to the peculiar configuration at the foot of the card inner. It would be extremely satisfying for the 'Halloween' card to read "I feel it in my bones, You ache to know my name, And so I'll clue you in... FK,"- so that is what we will create, by manipulating this card to read whatever we want it to.
The strange symbol, reading it as true as possible, appears like a number 7, followed by four dots and the letter F.
7+4=11=K (followed by F).
Without further ado, we shall move on to the next confirmed Zodiac communication on March 13th 1971, in which the Zodiac stated "This is the Zodiac speaking. Like I have allways said, I am crack proof. If the Blue Meannies are evere going to catch me, they had best get off their fat asses + do something. Because the longer they fiddle + fart around, the more slaves I will collect for my after life. I do have to give them credit for stumbling across my riverside activity, but they are only finding the easy ones, there are a hell of a lot more down there. The reason I'm writing to the Times is this, They don't bury me on the back pages like some of the others."
You will notice that the Zodiac Killer refers to "crackproof" once again, parroting his October 5th 1970 communication five months earlier. However, he doesn't just state he is crackproof, he reminds us that he has always been telling us he is crackproof, and quite possibly we just haven't got the message.

Roll on the January 29th 1974 'Exorcist' letter, signed "yours truley," nearly three years later, giving us our final installment of FK contained within the array of symbols at the foot of the letter. 
On this occasion he mirrors the sixth line of the 340 cipher by elevating the K above the letter F, and to its left. In fact, five characters from the Exorcist letter can be found in and around the corrected sixth line of the 340 cipher, as shown here in a previous article. This was possibly the fourth consecutive communication inferring an FK link and the suggestion that the author was indeed "crackproof."  
Was this a persistent and deliberate attempt to be true to the challenge laid down by The American Cryptogram Association and Professor D.C.B Marsh, by inserting his name (albeit initials) into the 340 cipher and subsequent communications, or just a case that my mind is F@@Ked after six exhausting years of looking for patterns where none exist.

The identity of the Zodiac Killer still remains a mystery after nearly five decades of searching, despite numerous suspects being thrust into the limelight, some with more merit than others. This often involves digging deep into the history of the suspect, their profession, acquaintances, social life, personality and movements in and around the Zodiac timeline, to get a better understanding on their viability as a serial killer. But in the following analysis we shall do the complete opposite and examine what the Zodiac Killer didn't do. The only tangible evidence we have to go on, are the crimes themselves and the correspondence he mailed, so we shall use these to search for any anomalies or departures from the expected, bearing in mind that the Zodiac Killer courted attention, with an insatiable appetite for baiting the newspapers for nigh on five years. However, two things stand out during the Zodiac timeline, one of which happened, or should I say didn't happen after the 'Los Angeles' letter mailed on March 13th 1971, that is particularly telling. Or quite possibly after the 'Pines' card mailed on March 22nd 1971, if you are inclined to believe this card to be genuine Zodiac material. The second is something that has been covered before in an article entitled 'Away for the Winter', and concerns the Zodiac Killer's notable absences during three consecutive years. For now though we will concentrate on the March of 1971.  

The Zodiac Killer remained silent for nearly three years until the Exorcist letter surfaced on January 29th 1974, widely regarded as his final correspondence - although a further three communications would be received in the February, May and July of that year. The S.L.A. letter was postmarked February 3rd 1974, the Citizen card was postmarked May 8th 1974 and the Red Phantom letter was postmarked July 8th 1974. Every other correspondence after this year has generally been received with widespread skepticism. Recently, an article on Zodiac Revisited sparked my interest detailing the Zodiac Killer movie released in the April of 1971, just one month after the 'Los Angeles' letter was mailed on March 13th 1971 and six months after the Halloween card mailed and addressed to Paul Avery on October 27th 1970. This article covers many aspects of the movie. Michael Cole, the author of this website and the Zodiac Revisited book due for release in 2019, highlights the involvement of Paul Avery as a consultant to the movie, and is credited as such on the Internet Movie Database.
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​So, bearing in mind the Zodiac's insatiable ego and penchant for letter writing, one would have expected the Zodiac Killer to have found it extremely difficult to resist contacting the newspapers to give us his review of the movie, considering he had no hesitation in giving us his opinion on The Exorcist and Badlands movies. The Exorcist movie was released in the USA on December 26th 1973 and one month later the Zodiac Killer would give his appraisal of the movie, calling it "the best satirical comedy that I have ever seen". The Badlands movie went on general release in the USA on March 24th 1974 and featured in his 'Citizen' card correspondence just over a month later, yet the Zodiac Killer failed to ever mention anything about a movie solely dedicated to his murderous rampage, when 'The Zodiac Killer' was released on April 7th 1971, directed by Tom Hanson. The Zodiac Killer replied to Vallejo Police Chief Jack E. Stiltz in the San Francisco Examiner on August 4th 1969, replied to Chief Martin Lee in the San Francisco Chronicle on November 9th 1969 and to journalist Paul Avery in a personalized Halloween card, yet in the instance, absolutely nothing. ​Eight months later, the Zodiac Killer would get a reprieve when the much higher profile movie 'Dirty Harry', starring Clint Eastwood, was released on December 23rd 1971 featuring aspects of the Zodiac case - a movie that wouldn't have escaped Zodiac's attention. Here was the perfect opportunity to bathe in his notoriety, but yet again, absolutely nothing. In fact, the Zodiac Killer would apparently keep up this silence for nearly three years until the Exorcist Letter in the January of 1974, commenting on a movie that has nothing to do with him. His moment in the sun had been lost. The Exorcist letter signed off with a threat: "P.S. If I do not see this note in your paper, I will do something nasty, which you know I'm capable of doing." I'm afraid he was three years too late.     

The three year hiatus was broken by the confirmed Exorcist letter, mailed on January 29th 1974, indicating he was still alive. So what interrupted his insatiable appetite for communication. It may be likely that he was incarcerated during this period for a lesser offence, curtailing his murderous exploits and communications with the newspapers. An inability to maintain his contact with the world surreptitiously from the confines of a cell, with constant vetting of correspondence, would certainly negate his literary prowess, thereby utterly refuting his exaggerated claim of 37 victims in the Exorcist letter. He may have massively increased his victim total by 20 since the 'Los Angeles' letter nearly three years ago, to give us the impression he was footloose and fancy free during this time period.
 
​One avenue to unearth the identity of the Zodiac Killer is to examine this three year period of 'absentia', which may ultimately prove more fruitful than examining the crimes and letters themselves. If we believe the Zodiac Killer to be a resident of the Bay Area, then it makes perfect sense to examine prison records of the locality and work outward - starting with San Quentin Prison, located in Marin County. The 'Los Angeles' letter was mailed on March 13th 1971 and the 'Exorcist' letter on January 29th 1974, so a prisoner jailed in late March of 1971 or possibly April or May, and released in late 1973 or early 1974, for a time period approximating two and a half years, may just give us the identity of the killer we have yearned. The answer may not lie in the crimes the Zodiac committed, but more in the crimes he didn't commit.

A special thanks to Michael Cole.- Zodiac Revisited.   

Recent events have shone some new light on the murder of Meadowbrook student Nikki Alexandra Benedict, just shy of forty seven years ago in Poway Road, Poway, California on Monday May 1st 1967. The young 14 year old girl was traveling back home to Olive Tree Lane, when her journey was cut short by an unknown assailant, who to this day remains a mystery.
She had left her friends house, situated on Halper Road in the early evening hours and it was in the region of the 12700 blocks of Poway, 100 yards from the Carriage Road intersection that her life was cruelly snatched away by fatal stab wounds to her chest. See area on Google Maps. Nikki Benedict was discovered alive at approximately 6.30 pm by a local boy Ronald Fisk (11), who raced to get help on his bicycle to his fathers shop nearby. Bob Fisk ran a butchers store in Poway throughout the 1960's and 70's. 

Cheri Jo Bates was brutally stabbed outside the Riverside City College Library after the killer had sabotaged her Volkswagen Beetle in the pretense of luring the young student to her death. One month later, on November 29th 1966, a typed Confession Letter was received at the Riverside Police and Riverside Enterprise detailing the murder, and culminating with the chilling words "Beware....I am stalking your girls now." Five months later came the murder of Nikki Benedict on May 1st 1967.
However, there is little to link the two cases other than a vague suggestion by the Zodiac Killer that there was a "lot more down there." On the face of it, this appears to be an unlikely Zodiac connection, but all avenues must be explored for the sake of the family and friends of Nikki Benedict, who surely after 47 years of questions deserve some form of resolution to her cruel murder.

This murder took place the day before the Zodiac Killer Button Letter was received at the San Francisco Chronicle on 26th June 1970, claiming he had "shot a man sitting in a parked car with a .38." However, the location in San Diego, and the traveling distance back to San Francisco makes any connection to the Button Letter, as well as the Zodiac Killer, unlikely.  Nevertheless, it provides a significant timeline between the murder of Larry Hargis and the mailing of the Button Letter to the San Francisco Chronicle the following day.
Any information regarding either of these cases, please contact the San Diego Homicide Detail by visiting their website below.
http://www.sdsheriff.net/coldcase/index.html. Thank-you.

It has been widely considered that the Exorcist letter mailed on January 29th 1974 may have been the final correspondence from the infamous Zodiac Killer. But is its claim of 37 murders, if indeed this is what was meant, a realistic one.
Firstly, we will take the unusual step of acknowledging the Zodiac Killer at his word, when throughout his campaign of terror he constantly informed the authorities of his murder count, displayed on each subsequent letter or card. But how accurate were his claims, and could a timeline of potential Zodiac victims be attributed to the periods in between each correspondence, bearing in mind that his declaration of seven murders on the Dripping Pen card of November 8th 1969 could be attributed with almost complete accuracy, albeit the missing murder in August, has still yet to be resolved.
As stated previously, the months displayed at the foot of the Dripping Pen card could indicate the murder of David Faraday and Betty Lou Jensen in December, Darlene Ferrin in July, Cecelia Shepard in September, along with Paul Stine and Cheri Jo Bates in October. This meant six murders possibly attributed and one unaccounted for, due to his proclamation on November 8th 1969, indicating a total of seven victims up to this point.
So let us examine the period from this letter to the next confirmed Zodiac correspondence on December 20th 1969, that of the Melvin Belli letter, claiming he may lose control and claim a ninth and tenth victim. The suggestion of a search for a ninth and tenth victim, by inference, meant he had already claimed his eighth murder victim and it must have occurred between November 8th 1969 and December 20th 1969. So who was the most likely Zodiac victim, based on age, locality and nature of the crime during this time period.
One possibility is Betsy Aardsma, murdered in the campus library of Pennsylvania State University on November 28th 1969- although this crime has a number of question marks, including the locality- seemingly out of kilter with what we know of the killer to this point. There is, however, another interesting case that deserves closer scrutiny.          

Incidentally, a woman's body was discovered next to Paradise Drive, Belvedere, Tiburon in December 1966, although the body, wearing a red dress had lain undiscovered for approximately three to four months, according to Marin County detectives.
Also on December 1st 1969 Elaine Davis (17) disappeared from from her home in Walnut Creek, Contra Costa County, California. She was abducted during the evening hours through a sliding rear window. Two and a half weeks later on December 19th 1969 her body was discovered floating off Light House Point, Santa Cruz, California, however, due to investigators misinterpreting the age of the victim at the time, her identity was only realized 31 years later when officials exhumed the body in 2000.
No link was ever ascertained between the murder of Elaine Davis and Leona Roberts, however, both victims fell within the correct age, area and timeline of the Zodiac Killer.    

On March 22nd Kathleen Johns was abducted and taken on a terrifying journey by an assailant she later claimed to be the Zodiac Killer. Even the Zodiac himself claimed his involvement, when he mailed a letter to the San Francisco Chronicle on July 24th 1970. There were many murders and disappearances in California during the month of March, including Cosette Ellison on March 3rd, Patricia King on March 5th, Judith Hakari on March 7th, Marie Anstey on March 13th and Eva Blau on March 20th. However, the 'My Name is...Letter' and Bus Bomb Diagram claimed 10 murders on April 20th 1970, with the Melvin Belli letter on December 20th 1969 indicating that 8 murders had taken place. If we therefore take the Zodiac at his word, only two murders had taken place in this four month period. If John Hood and Sandra Garcia were Zodiac victims, then none of the disappearances and murders in March were anything to do with the Zodiac Killer. On the other hand, if the Hood and Garcia murders were not Zodiac victims, then only two of these victims in March remain a possibility, not more. Unless for some reason only known to the killer, he committed more murders, yet failed to attribute them to himself. 

Nancy Bennallack had been slain in her own apartment on Arden Way and Bell Avenue, Sacramento , cut down by over 30 knife wounds, indicating the severity of the brutal murder- although she had not been sexually assaulted. The crime scene indicated that the killer may have used tape to mask over his fingertips during the attack.
Finally, onto the Los Angeles letter, mailed on March 13th 1971, where he laid claim to an estimated 17 or more murders.
In this letter he stated "I do have to give them credit for stumbling across my riverside activity, but they are only finding the easy ones, there are a hell of a lot more down there".
He was apparently referring to the fact that detectives had forged a link between the Zodiac Killer and the senseless slaying of Cheri Jo Bates in Riverside on October 30th 1966, claiming there were many more victims in that region.