Just a note to document this theory I found about the reason the Zodiac Killer stopped killing. This person hit the nail on the head. Harvey lost his license to drive due to his failing eyes. He lost it for an undetermined amount of time but did get his license back some time later. I will search and see if I can find the dates he was not licensed to drive and when they gave him his driving privileges back again…….(adding this to the growing pile of evidence!)