The Riverside link to Zodiac has yet to be fully established, despite the obvious inferences suggested in the History Channel documentary - although certainly the place a fledgling Zodiac would most likely have made his mistakes, could a connection be definitively ascertained. This was a point emphasized in the show early on. However, as highlighted in many previous documentaries, trying to shoehorn suspects into certain aspects of the case while blindly disregarding the obvious discrepancies, is fraught with danger. After watching the first episode, it is easy to see how Ross Sullivan has captured the imagination of many, desperate to link the subject to the Riverside murder and the infamous Zodiac Killer- but there are serious drawbacks to this particular suspect.
It is important to understand the ferocity of the Cheri Jo Bates murder, in which she undoubtedly scratched her assailant. Whether Ross Sullivan 'disappeared' for two weeks or not, investigators would have still checked everybody for scratches to their arms, body and face, and fingerprinted the suspect - yet still he evaded detection. Detective Gren stated "There is a strong indication that Miss Bates scratched and clawed her murderer in the struggle for her life". They would also have taken handwriting samples. If the limited Riverside correspondence can be matched to the Zodiac Killer, then so too can the handwriting of Ross Sullivan, which clearly must have been undertaken.
The documentary stated that Ross Sullivan can be placed in Santa Cruz, situated on the northern edge of Monterey Bay. This is 125 miles south of Lake Berryessa, 96 miles south of Vallejo and 75 miles south of San Francisco. If this were the case, we then would have to assume that Ross Sullivan, despite work commitments, took a round trip of at least 150 miles or more to perpetrate four Zodiac attacks and mail fourteen letters on varying days of the week, between July 4tth 1969 and March 13th 1971. Finally implicating and drawing attention to himself and his Riverside exploits in the Los Angeles letter, stating "I do have to give them credit for stumbling across my riverside activity, but they are only finding the easy ones, there are a hell of a lot more down there". Implicating oneself in the Riverside murder of Cheri Jo Bates is not the 'genius' move of a highly intelligent individual, if you worked in the Riverside City College library and knew the victim.
The "twich" and "squirm" link between the Riverside Confession letter and the Zodiac's Little List letter on July 26th 1970 could be a simple as Zodiac parroting key phrases he read in previously published articles on the Cheri Jo Bates murder. The odds of these words then matching falls to something far less statistically significant. It is still a noteworthy connection, warranting further investigation, but must be viewed with far more caution than that advocated. This is not meant to argue that Ross Sullivan should not be considered as a potential suspect in the Zodiac case, only that a necessary counterbalance is required when considering any leads in an already suspect laden case.
The five-part documentary should hopefully generate new interest in the Zodiac Killer investigation and create fresh impetus in a case now spanning five decades - and a case that is without doubt grinding under the heavy weight of expectation. The next episode will air on November 21st 2017.