It is really disturbing they didn't catch this, I understand DNA wasn't until late 80's, but since even in the first series of rapes in Sacramento, during the late 70's, there was widespread suspicion within the police, that it was possible ex military or ex or current police.
I won't say this is an easy catch, but if you say examined all policemen who quit or were fired from 1970-1980, which can't be more than 500 people, you would see the guy was dismissed from the force for stealing dog repellent and a hammer from a store. Then look at his work hours when rapes were committed.
Also, interested to see what he did post 1980, there was a lot of theories, credible ones, that he was in construction/real estate development as the murders tended to be linked time wise to major developments in all or most of the areas in which crimes were committed.
The full scope of his crimes is insane. The Visalia Ransacker, which is also believed to be him, ransacked over 50 homes and murdered someone, BEFORE the rape series.