On the contrary, this could go a long way to actually validating this correspondence. Bearing in mind the make-up of the 'Pines' card, it is extremely likely it is referring to the disappearance of Donna Lass. But in order for its author to have deliberately chosen the phrase 'Sought Victim 12' in reference to Donna Lass, we could assume he knew her previous employment and movements in the preceding few months, or just made a lucky guess when choosing this particular phrase.
Would a hoaxer, having gone to all the effort of pasting up a card, then have made the basic error of getting the victim total incorrect. One could argue that the author of this card knew Donna Lass, knew that she had previously worked at the Letterman General Hospital and knew exactly when she had moved to South Lake Tahoe.
Donna Lass left her job at the Letterman General Hospital and moved to South Lake Tahoe on June 6th 1970. Had he targeted Donna Lass before her move to the Sahara Tahoe Hotel? If so, then 'Sought Victim 12,' in its use of the past tense, could simply be implying that he had intended Donna Lass as a target before she moved from San Francisco.
Harvey Hines stated in his 120 page report "Now we have the Zodiac running into the Presidio in the direction of Letterman General Hospital. The very place that Donna Lass worked. Also, in looking at the area map, I found that Lass lived six blocks south in the 4000 block of Balboa. That meant the Zodiac Killer started his ride near where Kane lived and ended it several blocks away where Donna Lass lived and worked.
During the time she worked in San Francisco she lived at 4122 Balboa Street with a roommate named Carol Emerich. Emerich was also a nurse. According to the employment records, Lass was working a late night shift in October of 1969 when the San Francisco cab driver, Paul Stine, was killed by the Zodiac."
If the killer knew Donna Lass, or indeed was familiar with the Presidio Park and Letterman General Hospital, then it is not beyond the realms of possibility he likely was familiar with this area and the advantages it provided as an escape route after the murder of Paul Stine on October 11th 1969.
The Zodiac mailed the '13 Symbol' cipher on April 20th 1970 claiming 10 victims. On June 26th 1970 he was claiming 12 victims in the 'Button' letter. Therefore, he must have 'Sought Victim 12' between these two dates. The window of opportunity narrows when we consider that Donna Lass left for South Lake Tahoe on June 6th 1970. If the Zodiac Killer targeted Donna Lass while she worked and lived in San Francisco, it likely fell between April 20th 1970 and June 6th 1970. A window of just 46 days. Is this something a casual hoaxer would be aware of.
Unless the employment records and movements of Donna Lass between these dates had been reported in the newspapers, was the choice of the 'Sought Victim 12' phrase just a lucky guess on behalf of the hoaxer, and just happened to fall correctly between these dates. Did the author of the 'Pines' card do his research, or was Donna Lass specifically targeted by the Zodiac Killer, who moved or traveled to South Lake Tahoe with the sole purpose of completing his 'mission,' and the wording on the 'Pines' card was anything but a mistake.
It may possibly dispel the preconception that the Zodiac Killer only targeted strangers, as has been alluded to in the case of Darlene Ferrin, murdered on July 4th 1969. Maybe the Zodiac Killer didn't care who he killed.