The Zodiac saw the publicity generated from the brutal stabbing of Deborah Furlong and Kathy Snoozy on August 3rd and capitalized on this at Lake Berryessa in September. It had now paid dividends on April 11th 1971, when Kathy Bilek (18) visited Villa Montalvo in Saratoga, having planned to read a paperback book (The Gabriel Hounds) and engage in a spot of bird watching in the seclusion of a remote, wooded portion of the park, near a small stream. Her body was found the next day by her father, Charles, while Santa Clara County Sheriff's deputies searched nearby. She had been stabbed 17 times in the back and 32 times in her chest and stomach. This crime was obviously linked to the Snoozy/Furlong murders because of the extensive knife wounds and the locality. But by committing the savage knife attack on Bryan Hartnell and Cecelia Shepard at Lake Berryessa and hinting at his involvement in the San Jose murders of Snoozy and Furlong, the Zodiac Killer had now been given the opportunity by Paul Avery to accept the Riverside murder in 1966, along with the Kathy Bilek murder by the Vallejo Times-Herald on April 13th 1971. His switching to a knife in the commission of murder would inevitably lead law enforcement to link him to more crimes - something he knew only too well.
The 'Monticello' card mailed on July 13th 1971 was open-ended. It didn't directly claim the murder of Kathy Bilek, thereby allowing him a get out clause should this crime be later attributed to somebody else. The Zodiac Killer had used this tactic before when he insinuated his involvement in the murder of Officer Richard Radetich by stating "I shot a man sitting in a parked car with a .38". Then in the 'Pines' card, by again offering a cryptic message open to interpretation. He never actually claimed the murder of Cheri Jo Bates, simply stating "I do have to give them credit for stumbling across my riverside activity". Everything designed in such a fashion to avoid full admission.
The "August" reference on the 'Dripping Pen' card, while not actually writing it on the car door of Bryan Hartnell's vehicle, had metaphorically opened the door to the speculation shown by law enforcement in the article by the Vallejo Times-Herald. The September 27th 1969 attack, effectively enabled the Zodiac Killer to extend his reign of terror far beyond the shores of Lake Berryessa, into the heart of San Jose. The July 13th 1971 'Monticello' card was now the fifth communication referencing San Jose in the last 20 months - but there was still time for one more.
The final communication of 1971 may have been the elusive 'Sacramento DMV' letter, probably mailed in the November or December of 1971. This correspondence likely mirrored the November 21st 1969 San Jose letter and code, in which the Zodiac Killer mailed a correspondence to the San Jose Police Department and threatened a "widow". I have little doubt this woman had some involvement in the Deborah Furlong and Kathy Snoozy murders from the perspective of an eyewitness, and by Zodiac threatening her, he was effectively giving the impression that the murders were somehow pertinent to him. The Sacramento DMV letter was used for the same purpose - to keep the Zodiac story alive by means of interjection.
In October 1971, a magazine publication entitled 'True Detective' comprehensively featured the murders of Kathy Snoozy, Deborah Furlong and Kathy Bilek, and the subsequent arrest of Karl Francis Werner. There is every chance the Zodiac Killer read this magazine article, compelling him to continue his contact with authorities regarding these murders.
One particular section about Kathy Bilek caught my eye - that may have been the reason why the Zodiac Killer wrote a letter to the chairman of the DMV in Sacramento. It stated "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."
This was the final entry point of the Zodiac Killer. The 'Monticello' card and 'Sacramento DMV' letter had failed to hit the newspapers - and the reign of the Zodiac Killer had reached its end. The arrest of Karl Francis Werner for the three murders in San Jose had finally exposed the Zodiac Killer for the fraud he had metamorphosed into. The long shadow he had cast over the Bay Area of Northern California was starting to recede - and he knew his days were numbered.