Nobody can verify Xenophon Anthony as the Zodiac Killer, he may simply have been identified close to the crime scene or for that matter misidentified by the eight year old. But hypothetically, let us assume the eight year old was correct, and observed Xenophon Anthony in the proximity of the taxicab that fateful night.
The only way a child observing from the window of a residence can actually recognize somebody they knew, particularly at 9.58 pm at night, in less than ideal light conditions, is if they were viewing the unfolding events from a relatively close distance from the taxicab. In other words a residence close by. The closest residence to the crime scene was 3898 Washington Street, actually overlooking the taxicab, situated less than 30 feet away, the perfect vantage point to correctly identity a subject, known to the observer. The residence is also the most likely to be disturbed by a taxicab pulling up sharply, a muffled gunshot or any form of commotion on the street. The three teenagers across the street, by whatever means, had their attention drawn to the unfolding drama, therefore it is perfectly logical, that they may not have been the only ones.
Crucially, a simple records check placed an 8 year and 2 months old boy resident at 3898 Washington Street on October 11th 1969. This, although not conclusive, is likely the eight year old mentioned in the FBI document.
Whether or not Donald Fouke stopped the Zodiac is not important here, but the 'meeting' took place just shy of the Jackson and Maple intersection.
Witnesses in Spruce Street, detailed in the San Francisco Chronicle on October 12th 1969, reported seeing a man running into Julius Khan playground. The description was so similar to the ones given by Donald Fouke and the three teenagers, it seems inconceivable that this was not the same person that left the taxicab moments earlier. The only way it can be argued that this man entering the park wasn't the killer, is if we dismiss the testimonies of the witnesses in Spruce Street, while choosing to believe Donald Fouke and the three teenagers. The descriptions of the murderer given at all three points in the journey, not only overlap closely, but are testimony to the exact direction taken by the killer. Firstly, 3898 Washington Street, secondly, Jackson Street and thirdly, Julius Khan playground. To dispel this final sighting, is to dispel them all.
This is where the Zodiac Killer takes over in his November 9th 1969 'Bus Bomb' letter. He charts his position throughout his entire journey, from the taxicab to the moment he left the park, almost like he was fitted with a GPS.
It is important to note that sniffer dogs were assembled on the outskirts of the park at certain points. The area of Arguello Boulevard and the Julius Khan playground were two notable areas, to sweep west to east, and south to north, covering the entirety of the park. (see here). The route Zodiac took will be told in his own words.
1. "2 cops pulled a goof abot 3 min after I left the cab. I was walking down the hill to the park when this cop car pulled up."
Donald Fouke corroborated this, stating he passed a WMA just past the intersection of Jackson and Maple, at a point exactly 3 minutes walking distance from the taxicab.
2. "I said yes there was this man who was runnig by waveing a gun & the cops peeled rubber + went around the corner as I directed them + I disappeared into the park a block + a half away never to be seen again."
One and a half blocks from the location of where Donald Fouke passed him, is Spruce Street. Zodiac stated he entered the park here, and several eyewitnesses agreed with him, even giving a near perfect description of him.
In view of the assembled sniffer dogs and activity along West Pacific Avenue, Zodiac had limited options, so headed east. The nearest dogs to Zodiac were the ones assembled by Julius Khan playground, so if they never came within two blocks of him, he must now have moved 2+ blocks east, by or just beyond Laurel Street.
You will notice Zodiac stated "there was only 2 groups of parking about 10 min apart." Here they were, two groups of police with sniffer dogs measured at 8 minutes separation by Google Maps.
4. "then the motor cicles went by about 150 ft away going from south to north west."
This area provides plenty of coverage from the road and is approximately 150 feet away from any motorcycles passing by. He correctly states that the motorcycles would be travelling from south to northwest, along Presidio Boulevard.
But where does the killer go now.
The Zodiac Killer can head east, but it will be noticed that his directions and bragging have inadvertently taken us right by the residence of 3218 Jackson Street. A quick exit across West Pacific Avenue, through either Walnut Street or Presidio Avenue, to Jackson Street, places him only a couple of hundred feet from the doorstep, if indeed this was the killer's residence. Of course Xenophon Anthony may not be the killer, in which case, the 'Bus Bomb' letter author has, by sheer chance, taken us on a guided tour through the park directly adjacent to his residence.
This takes us to our final thoughts, regarding the wanted poster released on October 13th 1969.
The poster bearing the name Chief of Police Thomas J Cahill stated "Suspect takes cab in downtown area at 9.30 pm and sits in front seat with driver. Tells driver destination is Washington and Laurel area or area near park or Presidio. Upon reaching destination, suspect orders driver to continue on at gunpoint into or near park where he perpetrates robbery."
Assuming the killer had initially planned his murder on Washington Street and lived in the area, it would make sense to leave some form of 'buffer zone' from the site of the murder to his residence, a bare minimum of a block, preferably more, but all the time being wary of traveling any great distance on foot with the murder weapon and blooded shirt in tow. It's a delicate compromise.
It can be seen on the left and here on Google Maps that the intersection of Laurel and Washington Street is one block to Jackson Street, then one and a half blocks to 3218 Jackson Street, not too close, not too far, especially on foot, where time becomes more of a premium. It is actually a 5 minute journey.
If the information on the wanted poster has any origin in fact, then Zodiac certainly did overshoot his destination, but this time it would have been four blocks. Understandable if he is in the process of threatening a nervous taxicab driver.
Either way the location of Washington Street, close to Presidio Park, would have provided the perfect contingency plan, to shelter from the police, if things didn't go to plan. Enter Donald Fouke and Eric Zelms.
If we believe the Zodiac and 'Bus Bomb' letter, and the eyewitnesses in Spruce Street, then the likelihood he had a car parked up, somewhere by Jackson and Maple Street, is not likely. Once Donald Fouke and Eric Zelms had faded into the distance, all he had to do was locate his vehicle and drive off. Instead he headed to Spruce Street and through the park. But did he head for 3218 Jackson Street.