On April 15th 1971, addressed to "homicide inspector", the sheriff's office received an unsigned, somewhat incoherent letter which Rosa says may or may not be connected with the Kathy Bilek slaying (see below). The letter, on ruled paper, mentioned Zodiac and another victim, stating "Gril (sic) works in hospital" could be his next victim. It continued with "Beleaved to be Zodiac, Killer and gril lover writes long poem asking how anyone ever could ever begin to understand our world of pot etc".
Looking at the wording used in the letter it's impossible to determine whether this "Zodiac" correspondence is genuine or otherwise. Observers will obviously point out that the tone of the letter points away from the Zodiac Killer and towards a "drug fueled hoaxer". While this seems like the obvious superficial conclusion based on the wording in the letter, there is simply no way to determine the authorship of this communication. The only mildly interesting thing about this letter is the mention of "girl works in hospital" and "next victim", bearing in mind the Zodiac Killer letter mailed a letter to the Albany Times Union on August 1st 1973, which stated "I am not dead or in the hospital" and warned of a "next victim" from the "Albany Medical Center". This "next victim" believed to be a nurse (girl in hospital) during the "shift change".