Geographic profiling ia an invaluable tool for mapping the probable location where an offender most likely lives. This offender, like all of us, has areas of familiarity with respect to their profession and personal life that governs one's comfort zone, and therefore the commuter routes they opt for. These are factored into their way of thinking when considering any crimes that are to be committed or the areas where an offender may conceal a body. There is a delicate balance to be struck between the least effort principle (expenditure of the least amount of effort to accomplish a task) and the buffer zone (where an offender will avoid committing crimes too close to their home). In other words, they don't want to focus the attention around the place they live, but may equally not want to expend the effort in traveling a great distance, thereby creating a mental map of a target zone - usually somewhere with which they have a familiarity. Of course, factors such as their working week will affect the distance they are prepared to travel on any given day.

​This mental map was considered in the article Seventy One Days of Terror from October 11th 1969 to December 20th 1969, analyzing confirmed and unconfirmed letters, phone calls, murders and proposed murders during this time period. It became apparent that the locations targeted during this period, that included Sacramento, Fairfield, Vallejo, Oakland, San Francisco, Palo Alto and San Jose, all have Interstate 80 and U.S. Route 101 running directly through them. This may give us a clue to the areas where the Zodiac Killer was most comfortable. If he frequented these areas regularly in his profession, then this could very well influence the newspapers he read and the stories he became interested in. The case of murder victim Reet Jurvetson in a previous article, another example of a crime conforming to the above criteria. He may not have murdered this young woman, but was familiar with the area in which she was murdered, which ultimately governed his decision to choose her as victim number eight - allied to his new found fascination of knife crime. She too was brutally stabbed 157 times and unceremoniously dumped down a ravine off Mulholland Drive in Los Angeles. Her body was discovered just 2 miles from U.S. Route 101.           

When the Zodiac Killer failed to acquire the "front page coverage" he craved, he may have drew inspiration from the murders of Debra Gaye Furlong (14) and Kathy Ann Snoozy (15), who were found brutally stabbed and murdered on August 3rd 1969 in the Bay Area of San Jose. They each had suffered in excess of 100 knife wounds that can only be described as savagery. In less than two months he would arrive on the shores of Lake Berryessa armed with a 12-inch bayonet. The killer wrote on the car door of victim Bryan Hartnell "by knife". On November 8th 1969, he claimed his involvement in the Snoozy-Furlong murders by the addition of "Aug" on the 'Dripping Pen' greeting card, followed by the November 21st 1969 San Jose letter possibly suggesting that Reet Jurvetson was another one of his knife victims. Then came the "Bleeding Knife of Zodiac" mailed from Fairfield on December 16th 1969, followed by the 'Melvin Belli' letter on December 20th 1969, stating he was losing control and looking for victims nine and ten.  

On April 20th 1970 he was claiming a victim count of ten - so if we are to determine the murder victims or proclaimed murder victims of the Zodiac Killer, then we must take all of the above into account. Based on three of the four attacks to date, victims nine and ten may have been a couple. They would have been murdered between December 20th 1969 and April 20th 1970, in a non-sexual attack that involved numerous knife wounds. It is also critical (whether the Zodiac Killer was responsible or claiming to be the responsible) that they would would be found close to Interstate 80 or U.S. Route 101.
​
On February 22nd 1970, John Franklin Hood (24), who had served decorated time in Vietnam in the 64th Armoured Division and Sandra Garcia (20), who worked in the California Department of Motor Vehicles, were discovered brutally stabbed on a beach close to Santa Barbara Cemetery and East Cabrillo Boulevard. This crime in some ways mirrored the stabbings at Lake Berryessa on September 27th 1969, with Sandra Garcia receiving the brunt of the vicious attack. The beach where their bodies were found, lies only 500 meters from U.S. Route 101. The mental map of the Zodiac Killer is starting to take shape.

THIS ARTICLE HAS SINCE BEEN SUPERSEDED BY 'THE SACRAMENTO DMV' ARTICLE. Here is an accompanying extract from another valid DMV article (shown in red):

In October 1971, a magazine publication entitled 'True Detective' comprehensively featured the murders of Kathy Snoozy, Deborah Furlong and Kathy Bilek, stating "At about the same moment, Park Ranger Ken Williamson was informing a member of the investigative team that he, too, had noticed a tall, bespectacled young man who had been a frequent visitor at Villa Montalvo. He was a loner and had impressed the Villa's ranger staff with his almost furtive conduct, said Williamson. The ranger had jotted down the license number of the strange youth's auto. The license number was forwarded to the California Department of Motor Vehicles headquarters in Sacramento, the state's capital 150 miles to the north of San Jose. The information teletyped back from the registration bureau was that the auto was the property of a Karl Francis Werner, living at an address on Shawnee Lane in San Jose".

The Zodiac Killer, probably in one last throw of the dice, sent a letter to the chairman of the DMV in a desperate attempt to reclaim some lost pride. It likely read as follows "I am the murderer of the two kids in San Jose in August and the girl on the 11th of April near the park in Saratoga. I drove away quite slowly from both crime scenes so as not to draw attention to my car. Stop listening to phonys". Yet, on this occasion he couldn't supply any extra details known only to him and the police, finally bringing the Zodiac Killer's unabated fortune of claiming unsolved crimes to a crashing halt, and thereby exposing him as the real phony that many suspected he always was. The Zodiac Killer's race was run - and Ken Williamson was the architect in his unthroning.
Ken Williamson and the DMV Letter

Also read The Story of San Jose for full context surrounding the DMV letter.

ORIGINAL ARTICLE (NOW NOT APPLICABLE}
Tom Voigt, creator of the hugely successful ZodiacKiller.com website has been striving to secure Zodiac material previously withheld from the public for many years. Authenticated by a state document examiner, the DMV letter was mailed to the chairman of the California Department of Motor Vehicles, yet its delivery date and contents have remained elusive to this day. It appears the overriding consensus, that the closer this correspondence was mailed to the four canonical crimes, the more likely it is to be genuine Zodiac material. Having read the limited forum threads on this topic, the murder of taxicab driver Paul Stine in Presidio Heights on October 11th 1969 comes to the fore.
Tom Voigt stated "While I don't yet have as many details as I would like, at some point the Zodiac wrote a letter to the chairman of the Department of Motor Vehicles (DMV) in California. The letter was authenticated, apparently via handwriting, and was kept quiet for reasons unknown. The reason I have only lately been attempting to get permission from my source is because I just recently learned from victim Paul Stine's sister that Paul's wife at the time of his murder worked for the DMV". 
There is a California Department of Motor Vehicles at 1377 Fell Street, San Francisco, the same street that Paul Stine resided (1842 Fell Street) and just 700 meters away- but whether the suspect letter was mailed to the San Francisco offices and forwarded to the Department of Justice in Sacramento, or mailed directly to Sacramento, maybe Tom can elaborate.       
The Paul Stine police report suggested that the "suspect may also be in possession of the keys to the Yellow Cab, and possibly has the wallet belonging to the victim," so whether the Zodiac Killer mailed any possessions of Paul Stine with his communication to the DMV  chairman is uncertain. Having no idea the date this letter was mailed, opens up the possibility it may be connected to the Lake Berryessa attack on September 27th 1969, the only confirmed Zodiac crime in which the killer seemingly failed to document in letter form.

Having left his message on the car door of Bryan Hartnell's 1956 White Karmann Ghia, it is not unrealistic to consider that any correspondence following this crime may have been automobile related, hence the connections being drawn to the California Department of Motor Vehicles letter. Tom Voigt stated that "Paul's wife at the time of his murder worked for the DMV," but can we connect a possible Zodiac victim to the California Department of Motor Vehicles in or around the five murders attributed to Zodiac.

​On Saturday February 21st 1970, five months after the Paul Stine murder, John Franklin Hood (24) and Sandra Garcia (20) had traveled to East Beach, Santa Barbara, near East Cabrillo Boulevard- with John telling his parents he was to spend the day with his fiancee. Sandra had informed her parents that they "wouldn't be gone long," however, when they didn't return home that night the families became understandably concerned.
Their bodies were discovered early Sunday morning by beachgoers, fully clothed underneath a blanket. They had been brutally beaten and stabbed, predominantly in the back and face.
​John Hood had been stabbed eleven times, but it appears Sandra Garcia suffered the brunt of the attack, not dissimilar to the senseless attack on Bryan Hartnell and Cecelia Shepard at Lake Berryessa on September 27th 1969. Had the Zodiac Killer returned to a familiar method of execution after his venture into the heart of San Francisco, and was the Melvin Belli letter on December 20th 1969 the foreboding of a man who was about to murder once again, stating he may "lose control again and take his ninth or possibly tenth victim." Were John Franklin Hood and Sandra Garcia those victims. 
"The eldest of six children, Hood was born in Seattle. He came to California with his family in 1950. He attended El Rio Elementary School and graduated from Camarillo High School in June, 1965. After graduation, he worked at Wimpy's Drive-In in Oxnard and then joined the Army in January 1966. He spent two years in Germany with the 64th Armored Division after boot training in Ft. Bliss, Texas, and then returned home for leave before being sent to Vietnam. While on leave, Hood met Sandra while they were both vacationing in Tijuana, Mexico. An expert marksman, Hood was sent to Vietnam on January 6, 1969 with the 64th Armored Division. Hood was closed-mouthed about the combat-filled year he spent there and about the Silver Star, Bronze Star, Purple Heart and other medals he had received for valor. After returning to Oxnard, he went back to work for the drive-in eatery. Although Hood and Sandra were planning to be married, they had not set a wedding date." Oxnard Press Courier, February 23, 1970. Sandra Garcia worked for the California Department of Motor Vehicles in Oxnard, Santa Barbara.
​Was the DMV letter claiming this double murder, but was withheld from publication by police, who were unsure of a connection to the Zodiac Killer, or because of the sensitive details contained within the communication. We may have to wait a little longer to find out. 

FOOTNOTE: On September 12th 1987, Jose Santo Bugarin (26) and Rodolfo Alvaro (31) were traveling on King Road, San Jose, California when their car slammed into four children playing on the front lawn of a residence, killing three and injuring one. The driver then backed over the bodies and left the scene. Both were apprehended a short time later. "Bugarin was arrested on three counts of second-degree murder. Alvaro also was arrested on murder charges." Chicago Tribune.  
This was covered extensively in the newspapers. Just over six weeks later a letter claiming to be from the Zodiac Killer was mailed to the Vallejo Times-Herald on October 28th 1987​.
Update: "SAN JOSE (AP) A man who ran over and killed three children entered a plea bargain on Wednesday, pleading no contest to second degree murder and two vehicular manslaughter charges. Jose Santos Bugarin, 26, of San Jose, had two of the original murder charges filed against him changed to manslaughter. He will be sentenced to 21 years and eight months in state prison. Bugarin was the driver of a car that plowed through a front yard on King Road in San Jose on Sept. 12, killing three children." San Bernardino Sun- December 3rd 1987.
​Did the Zodiac Killer or the author of the 1987 letter read the news stories of this senseless crime and callously draw inspiration from this tragedy (Cars make nice weapons), compelling him to write the above correspondence, piggybacking off newspaper articles, in not dissimilar fashion to his early communications. 
The Car movie featured a satanic driverless car running people over in the fictional desert town of Santa Ynez in Utah. IMDB.
However, Santa Ynez is not so fictional in California. The town of Santa Ynez is one of the communities of the Santa Ynez Valley, Santa Barbara.  It is situated just 20 minutes or 12 miles (as the crow flies) from the site of the Robert Domingos (18) and Linda Edwards (17) murders on June 4th 1963, widely touted as an early Zodiac crime. See article 'Death on Four Wheels'. 

Thanks to Tom Voigt at ZodiacKiller.com

We certainly cannot take the early victim count of the Zodiac Killer as gospel, but bearing in mind the confidence of many regarding the murders of Robert Domingos (18) and Linda Edwards (17) on June 4th 1963 as possibly the precursor to the Lake Berryessa attack, the murders of John Franklin Hood (24) and Sandra Garcia (20) on February 21st 1970 appear a little under-reported. The Melvin Belli letter mailed on December 20th 1969 indicated the Zodiac Killer may have been looking for a ninth and possibly tenth victim- so bearing in mind his propensity of searching for a couple, this double murder is certainly in the correct timeframe, exactly bisecting the Melvin Belli and '13 Symbol' cipher letter on April 20th 1970. In addition, this letter would claim ten victims.
The young couple had traveled to East Beach, Santa Barbara, near East Cabrillo Boulevard on Saturday afternoon, with John telling his parents he was to spend the day with his fiancee. Sandra had informed her parents that they "wouldn't be gone long." When they didn't return home that night the families were understandably concerned.
Their bodies were discovered early Sunday morning by beachgoers, fully clothed underneath a blanket. They had been brutally beaten and stabbed, predominantly in the back and face. John Hood had been stabbed eleven times, but it appears Sandra Garcia suffered far worse, not dissimilar to the attack on Bryan Hartnell and Cecelia Shepard at Lake Berryessa on September 27th 1969. Had the Zodiac Killer returned to a familiar method of execution after his venture into the heart of San Francisco, and was the Melvin Belli letter the foreboding of a man who had lost control once again. 
The Oxnard Press Courier of John Franklin's home town reported the murders on February 23rd 1970: "Oxnard Man, Fiancee Murdered Victims. Bodies Found on Beach; Man was decorated veteran John F. Hood found slain with fiancee. The brutally stabbed and beaten bodies of a highly decorated Vietnam veteran from Oxnard and his attractive fiancee were discovered Sunday on an east side Santa Barbara beach just below a cemetery. Police identified the victims as John Franklin Hood, 24. who was discharged from the Army last month with the rank of staff sergeant after a combat-filled year in Vietnam, and Sandra Garcia, 20. of Santa Barbara. Early-morning beachgoers discovered the fully-clothed bodies under a blanket and hailed a passing patrolman. Police immediately closed off the area and later gave some brief details. However, they did not release some information for what they termed was a “good reason.” Detectives have questioned relatives and friends of the victims in an effort to trace the steps that led them to that beach." 

Continued - Page 2 of above article: "by Oxnard police. After the bodies were moved police found a 9 inch bone-handled fish knife in the sand. Santa Barbara authorities said the knife, possibly the murder weapon, had a 4 inch blade. Hood was stabbed 11 times in the face and back. The girl had multiple stab wounds, and authorities said she was not sexually molested.
Both bodies were discovered face-down, apparently left that way to give the appearance that the victims were sleeping, authorities said. 
The Hood family drove to Santa Barbara last night to be with Sandra's parents, Mr and Mrs Cruz Garcia, 3088 Calle Pinon, who were reported under heavy sedation. The families said "they had no idea" as to what happened at the beach. There were no difficulties and neither of the victims had any enemies as far as the families knew. Police said their investigation would continue. 
The eldest of six children, Hood was born in Seattle. He came to California with his family in 1950. He attended El Rio Elementary School and graduated from Camarillo High School in June, 1965. After graduation, he worked at Wimpy's Drive-In in Oxnard and then joined the Army in January 1966. He spent two years in Germany with the 64th Armored Division after boot training in Ft. Bliss, Texas, and then returned home for leave before being sent to Vietnam. While on leave, Hood met Sandra while they were both vacationing in Tijuana, Mexico. An expert marksman, Hood was sent to Vietnam on January 6, 1969 with the 64th Armored Division. Hood was closed-mouthed about the combat-filled year he spent there and about the Silver Star, Bronze Star, Purple Heart and other medals he had received for valor. After returning to Oxnard, he went back to work for the drive-in eatery. Although Hood and Sandra were planning to be married, they had not set a wedding date.
Besides his parents, Hood is survived by his sisters, Mrs Linda Jean Ortiz, 19, Lauretta Ann Hood, 16, and Virginia Sue, 13; and two brothers Jerry Allen, 18, and Joseph William, 10. The elder Hood is employed with the Associated Concrete Co, Saticoy, and Mrs Hood drives a small school bus. Hood's fiancee had been an employee of the State Motor Vehicle Department in Santa Barbara. Her father is the owner of the Garcia Auto Wrecking Co, Besides her parents, she is survived by three brothers."  Oxnard Press Courier, February 23, 1970.  

​February 24th 1970: "Police Hunt Pair In Twin Murders Santa Barbara. Detectives today were combing their city for two young men wanted for questioning in the vicious knife-slaying of an Oxnard Vietnam war veteran and his pretty Santa Barbara fiancee. Detectives said the pair, both in their early 20s, were seen “washing cut wounds” at an east beach area service station near where the bodies of the couple, John Franklin Hood, 23, of 460 Helsam Ave, and Sandra Garcia, 20, of 3088 Calle Pinon, Santa Barbara, were found. Witnesses told detectives the two men walked into the station about I a.m. with cut wounds they said they had received as the result of a fight in the east beach area. Detectives said one of the men had a vertical cut across the center of his forehead, extending from his hairline to an eyebrow. The other man had a wound on the back of his right hand. They were seen driving an early 1950 vintage light blue sedan with primer spots on the right side and trunk deck. Pathological tests revealed Hood and Miss Garcia were killed sometime between IO p.m. Saturday and 2 a.m. Sunday. The tests were conducted by Dr. John P. Blanchard, pathologist there." 
Oxnard Press Courier, February 24, 1970. 

Early details of crimes are usually withheld, though it later became apparent the killer had murdered the young couple with a 4 inch bone-handled knife, partially buried in the sand underneath the blanket. Why the killer failed to take the knife with him can only be speculated upon.
Whether this was the Zodiac Killer venturing south to commit this double murder may never be known, but bearing in mind the murders were in the correct Zodiac timeline, the only reasonable approach with such limited information available is to examine his following correspondence- the April 20th '13 Symbol' cipher.
This correspondence and cipher has been analyzed with a view to the code giving us a name.
However, the introduction: "This is the Zodiac speaking. By the way have you cracked the last cipher I sent you. My name is ------," leaves us with the possibility we are not looking for a name within the code, we were in fact, simply supposed to fill in the blank. Later in the communication he states "I have killed ten people to date" and "I hope you have fun trying to figgure out who I killed."​​​ Was this a subtle clue - that we are supposed to be figuring out a date, to unlock who his ninth and tenth victims were. By the sheer law of averages of his known victims, he attacked a couple 75% of the time. He also never claimed a ninth victim independently  between December 20th 1969 and April 20th 1970. 
The Zodiac Killer used symbols in his ciphers, so we will strip the '13 Symbol' cipher back to basics to attempt to uncover his intentions. He gave us three Taurus symbols and an Aries symbol reversed. He also gave us three circles.
The '13 Symbol'  cipher was mailed on April 20th, which is the exact date the star sign switches from Aries to Taurus.
The blank or white circle is the symbol for a full moon. See 1970 calendar. The astrological signs and full moon symbol are both relevant to the calendar.
The Zodiac Killer has placed the Taurus symbols within the circles - so by simple wordplay we have 'full moon in Taurus'.
The only 1970 full moon in Taurus is April 21st. If we are 'trying to figure out who he killed,'  the figure 21 isn't a bad place to start. The next thing to tackle is the reasoning behind the Zodiac Killer giving us three full moon symbols. Because he is challenging us to discover who he killed, it isn't unreasonable to assume the three full moons play a significant part in this game. The '13 Symbol' cipher gave us the first full moon, so we will look back at the last two Zodiac events.

One month prior, Kathleen Johns, accompanied by her 10 month old daughter Jennifer, were traveling along Highway 132, west of Modesto, en route to Petaluma, California, when her routine journey turned upside down. She was to make the near fatal mistake of stopping on a deserted highway at approximately 11.45 pm at night, ushered to the side of the road by a passing motorist, flashing his headlights and gesturing towards her 1957 Chevrolet. Believing he was indicating a fault with her vehicle, Kathleen Johns drew over to the side of the road. The man explained that her wheel appeared loose, offering to tighten it up for her, and she duly obliged. This innocent error was to begin a chain of events that are still not fully understood to this day, and have initiated countless years of debate on whether the man who approached Kathleen Johns car that fateful night was actually the Zodiac Killer, and the 'proposed madman' responsible for unleashing terror in the Bay Area of Northern California, and bringing the 'Summer of Love' into the summer of fear just two short years later.
Kathleen Johns was 'abducted' just before midnight on March 22nd 1970 and escaped at approximately 1.50-2.00 am on March 23rd 1970. March 22nd was as full moon. This is our second full moon. The third, with the figure 21 in mind, must be the date that Zodiac was asking us to "figure out". Therefore, we will travel back to the previous full moon.
John Franklin Hood and Sandra Garcia were not only are a couple, but a couple who were murdered under the Lake Berryessa template, which fell on the full moon day of February 21st 1970, to give us our third full moon as depicted in the '13 Symbol' cipher. 
https://www.timeanddate.com/calendar/1970 

In the Melvin Belli letter mailed on December 20th 1969 the Zodiac Killer stated he was afraid of "losing control again and taking his ninth or possibly tenth victim." Bearing in mind that three of his four attacks thus far were on couples, and his threat of claiming two victims in one letter, it is hardly surprising his next correspondence on April 20th 1970 has a total of ten proclaimed victims. But had he actually killed anybody, or was it again a case of idle bragging. The 'My Name is..'.letter contained a 13 symbol code, where the central focus was seemingly three circled eights positioned symmetrically in its design. These have been interpreted as Taurus symbols, due to the fact the Zodiac Killer had also apparently added an Aries symbol within the code, albeit upside down. The Zodiac Killer may have circled the characters so they could be interpreted as both. Since the Zodiac horoscope is prominent in astrology, the use of these symbols by the Zodiac Killer cannot be regarded as unusual.    

The author of the correspondence would sign off with the words "PS I hope you have fun trying to figgure out who I killed."​​​ Was this a subtle clue using the misspelled 'figgure' to shunt us in the right direction. He gave us three circled 'figure of eights' and an extra 'g' in 'figgure'. In addition the symbol for a full moon is a circle​

The '13 Symbol' cipher was mailed in April, and a quick look at the entire moon cycle for San Francisco in April shows a full moon on April 21st. A Waxing Gibbous denotes 95% illumination approaching a full moon and a Waning Gibbous denotes 95% illumination as we leave the full moon, everything in between can be regarded as varying degrees of a full moon. These are the four key phases in April. Considering the Zodiac used the Taurus symbol in his code, it is therefore not surprising that the date of this letter, April 20th, is the exact date that Taurus takes over from Aries in the Zodiac horoscope, and the varying degrees of the full moon from waxing to waning are in exactly the same 3:1 ratio as the '13 Symbol' cipher code. This is displayed below, placing the dates from the calendar above onto the cipher. 

The center of the cipher is where we shall focus. It is the 21st and a full moon. These are our first two clues.
The Zodiac Killer stated ​ "I have killed ten people to date". So was this the 21st on a full moon. Considering the Melvin Belli letter was mailed on December 20th 1969, any double murder would have to fall on December 21st 1969, January 21st 1970, February 21st 1970 or March 21st 1970. The attack on Kathleen Johns on March 22nd fell on a full moon, but does not fit the criteria  There is only one month that follows the exact four lunar phases as above, waxing and waning from the 19th to the 22nd, where the full moon falls on the 21st, and that is February 1970.
​Let us return to the phrase "PS I hope you have fun trying to figgure out who I killed."​​​ We have the figure 21 for the date, but what about the circled eight and the letter 'g' from 'figgure.' The '13 Symbol' cipher begins with an A and ends with an M, half the alphabet. The cipher showed perfect symmetry when the alphabet was placed alongside it here.
When the identical technique is used here, the letter G falls over the central 8 (and the 21st). The number 8 is also represented by the letter H. Even the three 8's total 21, if we take their numerical position on the cipher. 

Putting everything together, we are looking for possibly a double murder, on a couple, similar to other Zodiac attacks, on February 21st 1970, during a full moon, where the two letters G and H may feature.  
On Saturday February 21st 1970, John Franklin Hood (24), who had served decorated time in Vietnam in the 64th Armored Division and Sandra Garcia (20), who worked in the California Department of Motor Vehicles, decided to visit the quiet retreat of East Beach, Santa Barbara one evening, where unfortunately they fell victim to a knife wielding assassin.
John F Hood and Sandra Garcia were shortly to be married and were enjoying the evening tranquility lying on a blanket under a full moon, when a man armed with a bone handled 4" blade approached them and shattered their dreams. Despite apparently fighting back against their attacker, both unfortunately had their lives cruelly snatched away on the remote Santa Barbara beach. John Hood suffered eleven knife wounds, the majority inflicted to the face and back, with Sandra Garcia receiving the brunt of the vicious attack, leaving her almost unrecognizable, in what appeared a senseless and motiveless crime. There appeared to be no sexual interference and robbery was ruled out.
The couple were discovered the following day, Sunday 22nd February, lying face down on their blanket. The bone handled fish knife used in their murder was retrieved from beneath the blanket, partially buried in the sand. 
​These murders came five months after the Lake Berryessa attack on September 27th 1969, and the similarities have not gone unnoticed, with the use of a knife and cut pieces of rope, along with the beach location.  

http://www.zodiacciphers.com/zodiac-news/the-mathematics-of-the-13-symbol-cipher

On Saturday February 21st 1970 John Franklin Hood (24) and Sandra Garcia (20) decided to visit the quiet retreat of East Beach, Santa Barbara one evening, when they fell victim to a knife wielding assassin, in a murder that was not dissimilar to the attack on Bryan Hartnell and Cecelia Shepard at Lake Berryessa five months earlier and more importantly contained within the umbrella of known Zodiac crimes and letters. John F Hood and Sandra Garcia were set to become married and were enjoying the evening tranquility lying on a blanket under a full moon, when a knife-man carrying a bone handled 4" blade approached them taking them by surprise, and despite evidently fighting back against their attacker, both unfortunately had their lives cruelly snatched away on that fateful night. John Hood suffered 11 stab wounds, the majority inflicted to the face and back, with Sandra Garcia receiving the brunt of the attack leaving her almost unrecognizable, in what appeared a senseless and motiveless crime. Like the Berryessa attack, robbery and a sexual motive were absent and the remote location apparent, but is it possible this little covered double murder could be the work of the Zodiac Killer. Speculation will take us no nearer the truth, so let us examine the Zodiac letters and suspected crimes around the relevant time period and see if we can unearth any possible clues to push the Hood and Garcia case back into the limelight and into forefront of our minds.  

What we know of the Zodiac Killer is that he kept a running total of victims contained in his correspondence. The Melvin Belli Letter mailed on December 20th 1969 and the 'My Name is..Letter mailed on April 20th 1970 are of particular interest in this regard. The Melvin Belli Letter stated "I am afraid I will lose control again and take my ninth and possibly tenth victim." This is important because the next correspondence to claim 10 victims was the 'My Name is..Letter' mailed 2 months after the Hood/Garcia murders on February 21st 1970 and the immediate correspondence after the Melvin Belli Letter. The suggestion in the Belli Letter does not tell us whether the ninth and tenth victims are to be separate attacks or one combined attack, but what the Zodiac has been known for is attacks on couples and the Hood/Garcia murders fits this template. However there is something more important to bear in mind when we look at the 13 Symbol Cipher on the 'My Name is..Letter' and the phrase contained within the letter stating "I have killed ten people to date." 
​Let us look at the notable dates of Zodiac events from the Melvin Belli Letter to just prior to his mailing of the 'My Name is..Letter. The Belli Letter was mailed on the anniversary of the Lake Herman Road murders on the 20th, the Hood/Garcia murders were on the 21st and the highly debated Modesto abduction of Kathleen Johns took place on the 22nd. The key numbers to remember here are 20,21 and 22, then came the 'My Name is..Letter'. Within this letter the Zodiac gave us a 13 Symbol Cipher containing 4 Zodiac signs, but apparent was the highlighted three 8's or three Taurus symbols circled.
An astrological chart shows a full moon denoted as a circle and the 'My Name is..Letter' was mailed on April 20th 1970 to the San Francisco Chronicle, so let us look at an astrological chart of San Francisco on this date, bearing in mind that a full moon is regarded a full moon either side of it waxing and waning above 95% illumination. In astrology the Zodiac sign of Aries runs on average from March 21st to April 19th and Taurus takes over on April 20th ( the date this letter was mailed ) until May 20th. There are four full moons in April (shown here on the astrological chart), one falls in Aries and three fall in Taurus, the exact configuration on the 13 Symbol Cipher. The most important thing here though is the full moon circled Taurus symbols. They fall on the 20th, 21st and 22nd, exactly the same dates as the Melvin Belli Letter, the Hood and Garcia murders and the Modesto abduction in the run up to this letter and the 21st is the center point of the cipher as a whole. Take a look here for a visual representation. 

The Hood/Garcia murders on February 21st 1970 occurred on a 100% full moon, as did the 21st April 1970, depicted by the central Taurus on the 'My Name is.. Letter'.  On July 5th 1970, three men Thomas Victor Dolan (17), of Manhattan Beach, Thomas Hayes (19), of Hermosa Beach and Homer Clyde Shadwick (19), of Saginaw Michigan were discovered by a passer by on a beach in Santa Barbara, which straddled the University of California S.B building, two had succumbed to their injuries, while the third Thomas Hayes had been rushed to hospital in nearby Goleta, in critical condition, after the three appeared to have been subjected to a frenzied machete/hatchet and knife attack while camping out in their sleeping bags on the night of the July 4th 1970, after hitchhiking back from fireworks celebrations in Candlestick Park in San Francisco, fortunately for Hayes he survived his injuries. The attack seemed motiveless, as the three young men's watches and money remained untouched.
This attack came approximately four months after Hood and Garcia, who were murdered on Saturday February 21st 1970, 16 miles west of these attacks. Both the Melvin Belli Letter and Shadwick/Dolan murders were anniversaries of the Zodiac Killer's first two crimes at Lake Herman Road and Blue Rock Springs. But this may be the tip of the iceberg regarding dates employed by the Zodiac Killer. Lake Herman Road, Blue Rock Springs, Lake Beryessa, Presidio Heights, the Hood/Garcia murders, the Shadwick/Dolan murders and the likely murder of Donna Lass, all had one date in common, but that is another story.  Zodiac Ciphers-Murder In The First.