There are three key ingredients to unveiling what actually happened in the late hours of October 11th 1969 and all three can be found by examining firstly the fingerprints on the taxicab, allied with the actions and movements of the killer, secondly the blood pattern analysis of the shirt and finally the blood pattern in and around the taxicab as it was sequentially photographed by responding personnel. Blood does not lie, it follows the law of time and gravity and can be used to help us understand the position Paul Stine's body was situated throughout and therefore unlock a plausible course of events, starting with the Zodiac Killer's claim in a letter mailed to the San Francisco Chronicle on October 13th 1969 stating that 'I am the murderer of the taxi driver over by Washington St and Maple St last night, to prove this here is a blood stained piece of his shirt'.
Not only would Paul Stine have been laying flat, but as you will notice from the rear photograph of the taxicab, roads have a natural camber, convex in design and the taxicab is conforming to this tilt. See here. Blood will not flow against gravity and most certainly could not produce the pattern shown on the right.
The second alternative is that after Paul Stine was shot he remained upright for a prolonged or measurable amount of time. But for this hypotheses to work, we would have to assume the Zodiac Killer after he shot Paul Stine just sat in the rear of the taxicab doing nothing for a notable length of time. We know that the three teenagers who observed the crime scene stated they saw the assailant in between the driver and passenger seat, with the head of Paul Stine over his lap, so we know he was in a lying position as the killer proceeded to remove a large rear section of Paul Stine's shirt. In other words if the murder took place at Washington and Cherry, the logical order of events is that the killer shot Paul Stine, whether in the rear or front of the taxicab and then immediately proceeded to negotiate Paul Stine into a lying position, if he was not already in one and remove the swatch of shirt, before wiping down the interior of the taxicab. He then exited the front passenger side door and motioned round to a position somewhere between the left rear passenger door and driver side door, appearing to wipe down the taxicab, presumably to remove any incriminating fingerprints.
However there are four major flaws with this scenario. Firstly, if Paul Stine had been in a horizontal position within seconds or a very brief time after being shot then the blood pattern on the shirt could not have happened. Secondly, the three teenagers never saw the killer at any point in the interior rear of the taxicab. Thirdly, a gunshot was never heard, although it could have been muffled by the close contact wound or the killer may have used a suppressor. And finally, why on earth was the killer wiping down the front driver side door, what reason could he ever have for touching either the panel or handle of this door.
The taxicab pulled away from the intersection of Mason and Geary on it's short journey to Washington and Maple. As they approached the corner, the taxicab driver Paul Stine knowing he was en route to a scheduled fare, possibly failed to place the taxicab into park to facilitate a quick exit and started to turn to the right to request payment. At the same time the killer had raised his 9mm semi-automatic towards the right side of Paul Stine's face. In a split second realizing the uncomfortable truth and with his right arm wedged between his body and the seat rear, instinctively raised his left hand in a desperate bid to block, deflect or grab the assailants gun, however he was unfortunately a fraction too late, as the muzzle ejected it's deadly contents. This may explain the dark mark found on the dorsal side of Paul Stine's left hand at autopsy. The killer believed his task was complete. but Paul Stine's foot had broken contact with the vehicle's brake pedal and the taxicab was now motioning forward out of control. In an instant the killer had to react to prevent an imminent crash, alerting the neighborhood and drawing unwanted attention to himself. We may never know if his intention at this point was to preserve his master plan of securing a section of Paul Stine's shirt and was not to be denied or having possibly used a silencer, was determined not to place in jeopardy his quiet exit away up Maple Street to his waiting vehicle somewhere close by. Whatever the case he had to make his decision now.
This is where the three teenagers come into play. They said they saw the 'suspect in the front of the Yellow cab, mid to passenger side, with the victim slumped partially over his lap. The suspect appeared to be searching the victim's pockets. The suspect then appeared to be wiping on the interior of the cab, leaning over the victim to the driver's compartment. The suspect then exited the cab by the front passenger side door, also wiping with a white rag, possibly a handkerchief. The suspect then walked around the cab to the driver's side and proceeded to wipe the exterior of the left door area. The suspect then fled north on Cherry Street'.
They never saw him exit the rear of the taxicab and the bloodstained shirt, along with all the aforementioned actions would explain why the Zodiac Killer did what he did, as described by the three teenagers.
He exited the rear left passenger side door at Washington and Maple to enter the driver side door, therefore had to later wipe down both these surfaces. The bloodstained shirt exhibited a continuous and measurable time period in which Paul Stine was propped up by the killer between the two intersections, with the blood flow downwards and outwards around the chest area. He wiped down the driver side compartment, the area in which he braced himself entering the driver side door and stepping over Paul Stine's body. And finally, no gunshot was heard.
The next question is did the killer shut the front passenger side door when he exited the cab, to walk around and wipe fingerprints from Paul Stine's driver door. The answer is almost certainly yes. If we look at the sequential photographs taken of the crime scene, they tell a story. Two photographs in particular give us a clue.
If this is how Paul Stine was found by responding officers, with the door open, then are we to assume he never bled from the moment the killer left the interior of the cab until photograph 1 was taken, but then resumed bleeding from photograph 1 to photograph 2. This is obviously not possible. This may suggest the door was closed when officers first arrived on the scene, with Paul Stine's head and arm propped against the door. Once it was opened his head and arm fell out to the position shown, possibly flicking out the small areas of blood seen in photograph 1, from the body or inner door panel to the roadside below. After a period of time photograph 2 was taken, to show much greater blood transference.
Of course it has been stated that when responding personnel arrived Paul Stine's head was resting on the passenger side floorboard, and he was moved into the position shown, to deliver medical assistance, which would also explain the lack of blood on the roadside in image 1.
The Zodiac Killer, now predominantly blooded on his left side (due to leaning against Paul Stine on his journey between the two intersections), presumably had traveled one block further than intended. If he had left his car or waiting vehicle parked somewhere near the top of Maple Street, a direct route from the Washington and Maple intersection, his only option after heading up Cherry Street, was to turn east onto Jackson. But why was he walking on the north side. Any responding police officers traveling west on Jackson Street would be approaching the crime scene on this side of the road, exposing the Zodiac Killer to the full glare of oncoming headlights. It appears on the face of it an illogical choice. But when you factor in that his left side took the brunt of blood transference, it now makes perfect sense for him to choose the north side of Jackson Street, to face his blooded left side away from the street. He could at the very least have angled himself to the left side as any cars or police vehicles approached, without drawing too much attention.
A killer turning away fully to the left, may have raised suspicion, that is unless entering the stairwell of 3712 Jackson Street is your next best option, to fully conceal the blood, apparent on one side of your clothing. Had he walked on the south side, his left side would have been fully exposed, so it appears there may have been method in his madness after all.
But was the sighting by Donald Fouke of a shuffling man on Jackson Street the Zodiac Killer? Given the descriptions of Donald Fouke and the three teenagers, coupled with the timeline, there is little doubt.
Inspired and developed from this fantastic article in 2009