I think this makes Garys father a weak suspect....
"Stewart does not link Van Best to individual crime scenes — except to say he may have lived near the Paul Stine murder site — nor does he provide any ties to murder weapons or physical evidence. Stewart claims a bloody partial print found at one murder scene matches Van Best’s, but in order to do so, Stewart had to invert a known Van Best print to get anything close."
I have not heard if EVB knew much about guns. Several different weapons were used by Zodiac. Zodiac seem to be someone that knew about guns and was comfortable around guns.
Gary has presented only pictures of EVB circa 1962. He could look much different in 1969. EVB would make frequent trips to Mexico. Gary could not get a passport picture? like AJ Wilks got for Gaikowski.
Seems like Gary stopped doing his Due Diligence research once he got the big Book deal and ever since stayed secluded in the Baton Rouge area promoting his book.