Of course other options exist. He may have traveled westwards towards Vallejo, but this presents a problem and possibly a conflict of interests. Why would the killer, understanding that shots may have been reported in the location of Blue Rock Springs head into a region, where most likely responding officers would have been approaching from, including Ed Rust, who was patrolling in downtown Vallejo, rather than head down a quiet, dark road on the eastern fringes of Vallejo and Benicia in relative anonymity, and again, in the same direction he headed after the December 20th 1968 double murder. The risk factor appears less. Had the killer lived in the Vallejo region, then of course he may have turned right, headed home, disposed of the 'smoking gun' and returned back to the payphone, accounting for the lost 30 minutes or so. But if this were the case, why didn't the killer head towards this region after the Lake Herman Road attack, rather than away from it, further from home. It, on the face of it appears contradictory. The Zodiac Killer in his correspondence mentions Vallejo in several of his letters, including the 'July 31st letters', the 'Debut of Zodiac letter' (three times), Bus Bomb letter and disputed 'Fairfield letter'. but despite the first murders being committed in Benicia, he seems reluctant to ever mention this area, instead forcing home the Vallejo connection. If he mailed his letters away from his doorstep in San Francisco, why the over emphasis on Vallejo and the placing of a phone call in the Vallejo region. Surely this must point away from Vallejo as a possible home location of our killer, as his actions appear to be coercing us in that direction for obvious reasons.
This topic has been covered before in 'East to Benicia' and 'Springs and Tuolumne', but this time we try to narrow down the Zodiac Killer's exact route after the Blue Rock Springs attack with a little more detail. It may well be wrong, but there is no harm in trying.
The phone call from Vallejo, the dialogue in his letters: 'In answer to your asking for more details about the good times I have had in Vallejo',.... 'I did not leave the cene of the killing with squealing tires + raceing engine as described in the Vallejo paper'.....'I was in this phone booth having some fun with the Vallejo cop' and 'Ask the Vallejo cop about my electric gun sight which I used to start my collecting of slaves', may have all been designed to point us in this direction. Surely the Zodiac Killer was from Vallejo. Or was this what he wanted you to believe all along.