The placement of the bloodied print discovered on the front exterior passenger door handle effectively negates the premise of a passenger who rode in the front seat of Paul Stine's taxicab. Had this been the case, after removing the piece of shirt and exiting the front passenger side door, there would be no need to shut the door using the exterior door handle, but there would be every reason to wipe it down, as observed by the three teenagers. This is because the natural way to open the front passenger door after exiting the right rear of the taxicab would be to use your right hand. When opening a right-sided door it is more natural to use your right hand. Standing by a right-sided door and using your left hand would bring the door into your midriff. When the killer shot Paul Stine he likely received a fine mist of back spatter to his right hand. If he then exits the right rear passenger door with the gun still in his hand, or while putting it away, he would use his left hand to open it and close it, which is why no blooded prints were found on the right rear inner passenger door handle, or the exterior of the right rear passenger door. The Zodiac Killer was described by the three teenagers wiping down the front passenger door. It is likely he didn't thoroughly remove the bloodied fingerprints, evident by their discovery.
If the Zodiac Killer had entered the taxicab at the theater district, shot Paul Stine at the intersection of Washington and Cherry, exited the right rear passenger door and entered the front passenger door. Had he then took the shirt piece, exited the taxicab and proceeded around to the exterior driver side door to wipe it down, presumably with his dominant right hand (or not), then left the scene, why should he have ever touched the panel between the driver side door and left rear passenger door with his bloodied hands. This was the version in the police report, and simply doesn't explain why bloodied prints were discovered on this dividing panel.
But the more expansive version given by the Robbins kids explains this anomaly perfectly.
The teenagers clearly stated, that after he rounded the taxicab, he opened the driver side door, likely using his left hand (for reasons given above). But to pull Paul Stine back into an upright position he needs stability and leverage. This would be attained by bracing your right hand on the dividing panel between the driver side and rear door, to pull Paul Stine upright using your left hand. Once finished, the Zodiac Killer closed the driver side door and wiped the door handle. This handle may very well have received blood transfer from the killer's left hand when he initially opened it, after all he likely used it when tearing the shirt. Nevertheless, he either wiped it down thoroughly before he left the scene, or enough so that bloodied fingerprints, if deposited, were not present. However he made a crucial mistake. By concentrating on the door handles, he overlooked the bloodied fingerprints deposited by his right hand on the dividing panel. This was detailed in the Robert Graysmith book Zodiac: "At one point he opened up the driver's door and leaned forward to wipe off the area of the dashboard again. To steady himself, he leaned his right hand on the rail separating the front and rear windows. The fragment of cloth was still in his left hand. Then he closed the door and walked away". He exited up Cherry Street and into the night. Paul Stine's body at some point, aided by the camber of the road, fell back across the front passenger seat with his head coming to rest in the front passenger floorboard, where Armond Pelissetti would ultimately discover the stricken taxicab driver.