It just hit me an idea. San Francisco has quite a lot of YMCAs. Old ones, that people lived at. They have quite a few of them around Presidio. In fact they have an old one in the Presidio. Those YMCAs are not very far from that park, Julius Kahn.

This clearly shows that there was no sexual motive behind the attacks, the attacks served his need for power. He had power over peoples life, again this can be seen by the escalation for the attacks.
1st Attack – Shot and Ran
2nd Attack – More Interaction with the Victims, Phone call and letters
3rd Attack – Lot of interaction with the Victims, First day light attack, Costume, Writing on car door, Phone call
4th Attack – Full control over the attack, even to the point of controlling the victims last few minutes on the planet (by this I mean he was a taxi driver and he is doing your will as he is driving you to where you want to go), attack in a major city, letter, taking evidence of the crime.
Letters up to this point had been matter of fact, I did this, with this, and this happened. He obviously got something from the Cipher, but he must have been upset when it was cracked for easily and quickly.
Now that he could fulfil his need in a different way we see that his next two letters were significantly different from anything previously.
Instead of a standard letter we now get a greetings card and a 6 page rant with diagrams of his bomb.

One can argue that he had infinity times fold more communication with Betty Lou Jensen and David Faraday upon getting them out of the car in Lake Herman Road in order to kil them, in comparison to his "shoot while mute before u run" attack on Mike Mageau and Darlene Ferrin in Blue Rock Springs some 6 (almost 7) months later.

Back in Lake Herman Road he must have showed up out of nowhere while the two young lovers were too occupied to give his presence some attention, then hopped out of his car with his flashlight gun, shouted towards them to get out and shot one bullet in the air, maybe pretending to be a robber like in Lake Berryessa 9 months later, then he proceeded to shoot above the rear window since they were frozen still, and once they weren’t getting out after that try he shot the window, then Betty Lou Jensen got out first and once David Faraday was about to get out of the vehicle or that he was already out but haven’t fully stood up, the zodiac shot him from close range, seeing this Betty Lou was terrified and began to run for her life, that’s when he shot her in the back 5 times (the sixth shot missed IIRC).

Using the police times of Robert Connelly (11:05) and James Owen (11:14) the Zodiac Killer clearly hadn’t killed the couple in the turnout during this period. The notion of a killer parking alongside the couple and immediately exiting his vehicle to shoot the Rambler and force the couple from their vehicle and subsequently shoot them, couldn’t have happened. James Owen had an unobstructed view along the road at least 40 seconds ahead of him and saw no vehicle. He also saw no vehicle or headlights enter the turnout from the Benicia end as he approached it (30 seconds approach time). This means when the Zodiac entered the turnout both he and the couple effectively did nothing for at least 30 seconds and up to a possible 9 minutes. This negates any concept of a killer immediately leaving his vehicle to attack the couple. Either the two parties engaged in some activity for one minute minimum until a shot was supposedly heard, or up to nine minutes. The order of events portrayed in many documentaries is simply not possible. Two likely answers are [1] The victims knew the killer, or [2] James Owen’s testimony is incorrect.

…This means when the Zodiac entered the turnout both he and the couple effectively did nothing for at least 30 seconds and up to a possible 9 minutes. This negates any concept of a killer immediately leaving his vehicle to attack the couple. Either the two parties engaged in some activity for one minute minimum until a shot was supposedly heard, or up to nine minutes. The order of events portrayed in many documentaries is simply not possible. Two likely answers are [1] The victims knew the killer, or [2] James Owen’s testimony is incorrect.

Is this possible?

Jensen and Faraday are parked, Zodiac pulls into the turnout, and within moments Owen’s approaching headlights become visible in the distance (Owen’s headlights would be visible to those in the turnout before James would be able to make out the cars.) Jensen and Faraday, seeking privacy, duck out of sight of the oncoming headlights, as does Z. Owens passes, and very shortly afterwards, Z emerges and attacks.

That scenario seems more plausible than the other two presented above, at least to me.

Certainly that is possible Marshall, although the couple didn’t do this on either pass by the Your’s.

Maybe Zodiac was on foot ?

Posted by: @cragle

“I am the same man who did in the people in the north bay area”
1. He seems to descend into some sort of comic book villain at this point, “Did In” sound like something a 1920’s mafia member would say. It looks to be totally out of line with any of the earlier mailings.

Great observations! I also think it sounds a bit strange. It reminded me of a “fun” fact: The mobster Umberto “Albert” Anastasia had the nickname “Lord High Executioner” ? 

Umberto “Albert” Anastasia[2] (/ˌænəˈsteɪʒə/, Italian: [umˈbɛrto anastaˈziːa]; né Anastasio [anaˈstaːzjo]; September 26, 1902 – October 25, 1957) was an Italian-American mobster, hitman, and crime boss. One of the founders of the modern American Mafia,
…
Anastasia was one of the most ruthless and feared organized crime figures in American history; his reputation earned him the nicknames “The Earthquake”, “The One-Man Army”, “Mad Hatter” and “Lord High Executioner”.