The Orlando Sentinel carried the headline "Zodiac, Killer Of 5 or 13, Silent As Police Wait". This was the headline the same day the Bay Area murderer mailed a postcard with the pasted newspaper text of "Zodiac" and "13", with a reference to "police" in the inverted text (present in the accompanying story). After 71 days of silence from the Zodiac Killer, he featured the prominent number "13" within his postcard and mimicked the headline from the Orlando Sentinel newspaper (or another derived from Reuters) within a 24-hour period. The newspaper asked the question 5 or 13? The Zodiac may have replied with "13" almost immediately. Although the Zodiac Killer sourced his pasted text from several newspaper articles in September, it appears the postcard may have been designed and created as late as the 4th or 5th October 1970. However, the Zodiac Killer chose to use multiple cut-out letters to create the pseudonym "Zodiac" on the 13-Hole postcard, when he had the identical font spelling "Zodiac" in the headline of the newspaper article. This could indicate the inspiration for the postcard lay within another newspaper publication carrying a different headline, but similar messaging regarding the questioned victim total.
Did the Zodiac Killer have a collection of old newspapers, or did he work as as news vendor or newsagent, giving him ready access to dated material from across the USA?
Thanks to author Jarett Kobek for his assistance in this matter, who also supplied the newspaper cutting used in this article.