There were multiple Zodiac killers
I was just watching on YouTube about "new" suspect Richard Gaikowski when it suddenly dawned on me.
There were TWELVE Zodiac killers. There are twelve signs in the Zodiac and since a group of 12 were planning and doing the killings, they decided upon "Zodiac" for the name.
It only makes sense.
If there were one less (eleven), they probably would have named themselves "49er" (11 on the field for football).
Anyway, so sad. Twelve killer/associatess and they have not positively identified a one of them, although odds are that each and every suspect mentioned in this film was one of the killers/planners/cypherers.
;-)