It was speculated that had the Zodiac Killer exited the Presidio Park on its eastern edge to a waiting vehicle, with his escape via the Golden Gate Bridge into Marin County a matter of minutes away, providing separation from the San Francisco area. If the Zodiac Killer worked in San Francisco (near Presidio Heights), but commuted from Vallejo, then he may have used Highway 101 on a regular basis, passing through Marin County. Highway 101 straddles Shoreline Highway by just 724 meters, which we will return to shortly.
Here is an excerpt from Websleuths by Steph54 "On 28 December 1969, a man searching for driftwood on the beach at Bolinas Lagoon in Marin County found the nude body of Leona Roberts. It was later determined that a unique wristwatch was missing from the girl's wrist, but a Napa High School class ring given to her by a neighbor still remained on her finger. The tan dress she wore when last seen, along with two pairs of bell-bottomed pants, a blouse, a black purse and wallet, a key chain with car and house keys were also reported missing. There were marks on the wrists and ankles indicative of binding, but the coroner was unsure whether they occurred before or after death. The cause of death was reported as "due to viral infection of an unidentified species." It was also reported that there was "evidence of choking which could probably be linked to the virus." link.
The same day, a potential Zodiac correspondence arrived at the Sacramento Bee newspaper containing a horoscope page with pasted wording. This communication entitled Day-By-Day Forecast For Cancer was pasted with the wording ZODIAC, WATCH, FLT 555 and BIRDS FLY SOUTH. The day after the Leona LaRell Roberts abduction, on December 11th 1969, a communication entitled Day-By-Day Forecast For Leo arrived at the San Francisco Newspaper Printing Company at Rincon Annex, again with many pasted words, including FLT THREE OF A KIND. It was thought that the Day-By-Day Forecast For Leo may have been a sinister play on words for Day-By-Day Forecast For Leona Roberts, considering the date of her abduction and the mailing of this communication the following day.
A day-by-day forecast may have been an appropriate message considering her abduction on December 10th 1969, to the eventual discovery of her body eighteen days later at Bolinas Lagoon in Marin County. This is where Shoreline Highway comes into play, being just 724 meters from Highway 101, and a route that the Zodiac Killer may have commuted to and from work. Shoreline Highway runs alongside Bolinas Bay to Bolinas Lagoon, where Leona Robert's body was discovered. When we consider the December 10th 1969 communication containing the words ZODIAC and BIRDS FLY SOUTH, coupled with the December 11th 1969 Day-By-Day Forecast For Leo and her body being discovered at Bolinas Lagoon, the following information may become relevant.
Bolinas Lagoon is a tidal estuary, approximately 1,100 acres in area, located in the West Marin region of Marin County, California, United States, adjacent to the town of Bolinas. The Pacific Flyway is a major north-south flyway for migratory birds in America, extending from Alaska to Patagonia. Every year, migratory birds travel some or all of this distance both in spring and in fall, following food sources, heading to breeding grounds, or travelling to overwintering sites. Along the Pacific Flyway, there are many key rest stops where birds of many species gather, sometimes in the millions, to feed and regain their strength before continuing. Some species may remain in these rest stops for the entire season, but most stay a few days before moving on. Wikipedia.
Bootjack Campground is located 553 meters from the Pantoll Campground along Panoramic Highway, which joins Shoreline Highway at its southern tip, Pat Tan's body was discovered hanging just 2.5 miles from the dump site of Leona Roberts at Bolinas Lagoon. Leona Roberts abduction was paralleled by two communications entitled Day-By-Day Forecast For Cancer and Day-By-Day Forecast For Leo, along with the pasted pseudonym of ZODIAC, as was the untimely death of Pat Tan, when the following day on the April 20th 1970, the Zodiac Killer mailed the 13-Symbol cipher containing THREE OF A KIND. However, this time it would be 888 instead of 555.
Two years later, on April 7th 1972, Isobel Watson (33) had just got off the bus on the evening of April 7th 1972, and was walking home along Pine Hill Road, Tamalpais Valley, Marin County at 9.00 pm, when a light colored vehicle veered towards her, knocking her to the ground. The driver exited his vehicle offering to take her home, but after she had refused his offer of apparent help a second time, the concerned citizen suddenly became enraged, pulling out a knife and stabbing the woman in the neck and shoulder. Her screams alerted the neighborhood, forcing the assailant into a hasty retreat from the scene. She was treated at Marin General Hospital and fortunately survived the brutal attack.
Her description of the man alerted investigators to a possible Zodiac connection, that of a man with heavy-rimmed black glasses, around 40 years of age, 5' 9" in height and short brown hair. It was not overlooked by police that the killer had attempted to lure the woman into his vehicle, not dissimilar to the method employed in the Modesto abduction of Kathleen Johns. Napa County homicide detective Kenneth Narlow believed in a greater than 50-50 chance of a Zodiac connection, bearing in mind the description given by Isobel Watson. Pine Hill Road, where the attack occurred, joins Shoreline Highway at its southern edge, just 4 miles from the Bootjack Campground and 7 miles from Bolinas Lagoon. Shoreline Highway joins Panoramic Highway only 1 mile from Pine Hill Road. So, had the attacker of Isobel Watson managed to lure her into his vehicle, would we have found her near Bootjack Campground or Bolinas Lagoon, just like Pat Tan and Leona Roberts? Of course, we don't know whether the Zodiac Killer had anything to do with the unfortunate events that befell these three women, but the location of Marin County and the proximity of Pine Hill Road, Bootjack Campground and Bolinas Lagoon is worthy of further investigation.