I was reading some newspaper articles about the DMV in case something would pop up that could give a hint of when and why Zodiac would have felt compelled to mail the director. Well, the DMV director from ’75 to ’78 was Herman Sillas Jr. Before DVM, he worked as an attorney in Los Angeles, and after that as U.S. attorney. It seems he had some fairly unorthodox ideas while at DMV. For example, he made all the male employees swap jobs with women for a few days. He also had the back of a Volkswagen painted on his office doors with the words "love bug". He also abolished the practise in which anyone could anonymously call DMV and receive name and personal information behind a license plate number.

Maybe something like that could rile up Zodiac.

The director before Sillas, Robert Cozens, seems to have been more typical of a boss.

Was Z a DMV employee at that time? Interesting thought.