The Zodiac Killer stated "I have killed ten people to date". So was this date 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, which is 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). Even the three 8's total 21, if we take their numerical position on the cipher.
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 the age of the couple, the apparent lack of motive and the beach location.