The diagram to the right shows the crosshair overlayed on the map, in which the X's approximately line up with his murders at Lake Herman Road, Blue Rock Springs, Lake Berryessa and Presidio Heights. So all we have to do now, if this was the intention of the marked crosshair, is to use the lines drawn from the center of Mount Diablo to point us in the right direction.
We know the Zodiac Killer was claiming seven murders and we know of five with a fair degree of certainty. In previous articles it had been suggested that the two remaining lines may be the unknown locations of two separate murders, unaccounted for. But another possibility exists. The Zodiac Killer's 6th and 7th murder victims could be located through any one of the remaining 9 points marked on the crosshairs circumference, or indeed the existing ones.
A 10th victim was confirmed by the arrival of the 'My Name is Cipher' on April 20th 1970. This correspondence could have read Zodiac 12 SFPD 0, if the Zodiac Killer had been successful in the murder of Kathleen Johns and her infant daughter, one month earlier on March 22nd 1970 - commonly referred to as the 'Modesto Attack'. This crime may not have been the work of Zodiac, but he claimed it was, and not something he was about to forget.
The Zodiac Killer's three early crimes were in static locations - that is - he did not coerce or force his victims to a predetermined location. It has been suggested by some Zodiac researchers that the Paul Stine murder was chosen because of his ability to manufacture an exact grid position to fit his location point on the 'Bus Bomb' letter crosshair. The next two incidents strongly linked to the Zodiac Killer were the Modesto abduction of Kathleen Johns on March 22nd 1970, followed by the Donna Lass disappearance on September 6th 1970, with one or both employing the use of a car to abduct the victim and again, maybe with the intention seeking out his predetermined grid location. But there is another reason that may link both Kathleen Johns and Donna Lass.
The Zodiac Killer could quite easily have shot Kathleen Johns through the driver side window of her vehicle as he had done at Blue Rock Springs Park, but chose to subject his victim to what appeared an aimless drive around the countryside of Tracy, CA, after which she escaped to a nearby field. If this was a Zodiac crime, was the Bay Area murderer possibly aiming for somewhere in the region of Antioch, CA, which falls directly on the north-east line on the map above, and conveniently on the way back to the Vallejo area where it has been widely speculated that he resided.
Kathleen Johns may have denied the Zodiac Killer his 11th and 12th victim this time, but was he to remind us of it exactly one year later on March 22nd 1971, when the disputed 'Pines' card landed at the door of the San Francisco Chronicle. The reason behind its design is not certain, but what was apparent, is that the largest writing on the 'Pines' card was "Sought Victim 12" written in the past tense. Was this an indication that he had indeed sought his 12th victim, but failed? This card signifying 12 was out of sequence with the the other cards, because it came after the 'Little List' letter on July 26th 1970 claiming a victim count of 13, the '13 Hole' postcard on October 5th 1970 also claiming 13, the 'Halloween' card on October 27th 1970 inferring a 14th victim and the 'Los Angeles' letter on March 13th 1971 claiming 17+ victims.
Had the Zodiac Killer intended to send a card earlier, immediately after the Modesto abduction, claiming his 12th victim, but was thwarted because Kathleen Johns and her daughter escaped into a field? Then he mailed the 'Button' letter on June 26th 1970 restoring his victim count of 12, but under a different scenario of "shooting a man in a parked car". The Button letter was the second time he included a marked crosshair, but this time centered over Mount Diablo as if to remind us of his master plan.
Is it possible the Zodiac Killer did not write "Sought Victim 12" on the 'Pines' card to highlight any failure, but he did it to mark the one year anniversary of the Modesto abduction, indicating a new victim had been found, that of Donna Lass, who by association with the Lake Tahoe area, has forever been linked with this card.