The two sets of letters were also accompanied by a symbol at the foot of the correspondence. The crosshairs of the Zodiac Killer are all too familiar, but what were the strange symbols at the foot of the Riverside Police Department and Riverside Press-Enterprise correspondence. They do not appear to be a regular letter Z, as both have an elaborate tail off the left side, as shown in the above image.
The Zodiac Killer was not averse to placing his running total of victims at the foot of each letter, and this may be the case in the Bates letters. In one of Zodiac's mailings he sent us the 'Halloween' card addressed to Paul Avery, but possibly replaced the victim count with an elaborate symbol on the inside of the card. We know he was inferring 14 victims over the entire card, so why should the symbol be any different. Below is a depiction of one possible interpretation.
On first glance the Bates symbol could be interpreted as a joined 3 and V, indicating three victims. After all, the murderer of Cheri Jo Bates was claiming previous victims, apparent in the 'Confession' letter he mailed one month after her murder. It stated "She is not the first and she will not be the last. I lay awake at night thinking about my next victim." The question is, were his next victims that of David Faraday and Betty Lou Jensen on December 20th 1968, just two years later.
The Zodiac Killer first gave us a running total of seven on the 'Dripping Pen' card, mailed on November 8th 1969. The Zodiac claimed "Des, July, Aug, Sept, Oct = 7" at the foot of the card. At this point in time we knew of five Zodiac murders, that included David Faraday and Betty Lou Jensen in December, Darlene Ferrin in July, Cecelia Shepard in September, and Paul Stine in October. We were missing two.
If we also included Cheri Jo Bates into October, then we would be missing only one victim in August. If the Zodiac Killer was the murderer of Cheri Jo Bates, then was his first victim just two months earlier in August 1966 and Cheri was "not the first and was not to be the last." This would give us the total of seven victims the Zodiac was referring to in the 'Dripping Pen' card. Is it possible the Zodiac Killer had already adopted his pseudonym as early as 1967, bearing in mind the symbol on the Bates letters does not conform fully.
One interpretation of the Bates symbols could have inspired his design on the 'Halloween' card, shown below. The number 2 (or possibly 3) tagged onto the left side of the arrangement, as opposed to 'fourteen' on the 'Halloween' card, tagged onto the right side. However it may be a little convoluted, and would presuppose his use of the pseudonym Zodiac in 1967, which could not be backed up with anything tangible.
On the right may be an early example of the Zodiac Killer's running victim total, inferring '2 victims' (or possibly '3 victims').
However, we were two murders short on the 'Dripping Pen' card, so this coupled with the five murders in the Bay Area brings us to the correct total of seven, by November 8th 1969. The total on the 'Dripping Pen' card may only be crimes under the Zodiac umbrella, which he adopted in 1969, which do not include any of the Riverside attacks. Nevertheless, the Bates symbols may still be an early example of a running victim count, which he refreshed when he became Zodiac. If this is the case, then the hunt for victims six and seven will have to start again, maybe somewhere other than Riverside.