The Zodiac sent three coded segments in three letters on July 31st 1969 to the San Francisco Examiner, San Francisco Chronicle and Vallejo Times-Herald giving details of the first two crimes to police. The Zodiac Killer seemingly though still had a lot to prove to Police Chief Jack E. Stiltz, who was less than satisfied that the letter writer and killer were one and the same. On Saturday August 2nd 1969 in the San Francisco Chronicle, he requested the writer send a second letter "with more facts to prove it". Another Zodiac article featured the following day on Sunday August 3rd 1969 in the San Francisco Examiner. Jack E Stiltz was "still not convinced the letters and codes were written by the actual killer". The police chief "urged the writer to send more letters, with more facts to prove his connections to the crimes". The Zodiac responded immediately, detailing the Lake Herman Road and Blue Rock Springs attacks with greater clarity. He did exactly the same thing in the 'Bus Bomb' letter mailed on November 9th 1969, outlining his excursion into Presidio Park when challenged by Chief of Police Martin Lee.
The question remained, was the '13 Hole' postcard a response to the disappearance of Donna Lass? Shortly after her disappearance somebody rang her landlord and the casino to report Donna Lass had been called out to attend a family emergency. This in all likelihood was used to buy time, knowing that police will question family and friends first, before spreading their net wider afield. It appears the perpetrator may have known Donna Lass or was somehow connected to her. So to avoid any incriminating searches, the phone call may have been implemented to afford some breathing space. Additionally, it has become apparent she walked to work that evening from a previous residence, so her car was never parked outside the casino that night. If the perpetrator knew Donna Lass and the vehicle she drove, then a phone call to the casino implying she had been called out of town for a family emergency and would be away from work for a period, would be negated if her Chevrolet Camaro convertible was spotted sitting idle in the car park of the casino for any extended period. This may suggest she was carefully tracked that evening and the crime planned in advance. Was the killer close enough to Donna Lass to know her family lived in Beresford, South Dakota and the phone call had a better chance of buying time under these circumstances. The perpetrator also appeared to be fully aware of her shift details, as she vanished moments after changing from her nurses uniform into regular clothes.
The San Francisco Chronicle ran an article on the missing Donna Lass on September 26th 1970 entitled Nurse Vanishes...A Tahoe Mystery. It stated "As the absence lengthened hotel officials contacted the South Lake Tahoe Police, who checked her apartment and could find no clue to her whereabouts. Relatives in Sioux Falls flew here a week ago".
So I suppose Zodiac's paraphrasing of the Mikado on July 26th 1970 stating "none of them will be missed" partly rang true, in the sense it bought him valuable time. The idea the Zodiac knew Donna Lass has its origin from the Letterman General Hospital, San Francisco, situated in the Presidio Park - the occupation she held prior to arriving in South Lake Tahoe just a few months earlier.
This takes us back to "There are reports city police pig cops are closeing in on me. Fk I'm crackproof. What is the price tag now?" Could the killer, aware of the family's appeals to the media have responded personally. The thought has crossed many peoples minds that Fk may be somebody's initials. Had a police officer been quoted or a newspaper reporter written an article about the Zodiac Killer, suggesting the net was closing, and this was his response using the initials of the said person to reply? However, trawling every article on the Zodiac Killer has failed to throw up any possible name that fits with the initials, suggesting it may be wrong.
Gregory Haugevik, a Zodiac enthusiast, pointed out that the 'k' was not capitalized pouring serious doubts on the idea, unless of course the author simply had no capital 'K' to hand when pasting the card. Or in some subtle way, the lower case 'k' he used was a clue to the identity of the person he was addressing. The following may very well be incorrect, but this postcard was the first correspondence mailed by the Zodiac Killer after the disappearance of Donna Lass - and as stated above, it was mailed only nine days after the San Francisco Chronicle article - so in the absence of any reporter or police officer, is it likely the killer could be addressing the family of Donna Lass in his usual taunting manner. Donna Lass' father was James Lass and the maiden name of her mother was Frances Kukar - to become Frances Lass upon marriage.
"There are reports city police pig cops are closeing in on me. Frances Kukar, I'm crackproof. What is the price tag now?" If the Zodiac Killer was aware of the maiden name, it may suggest him to be closer to the family than we dare to imagine, thereby casting a sinister overtone upon the card. On the other hand 'Fk' could simply mean F@@k.