Experts very quickly determined it was a hoax letter. "The fake letter sent to the Vallejo Times-Herald in midweek was a simulation of a hoax letter written in 1978", police Capt. Roy Conway said Thursday. "The determination was made by experts in the state Department of Justice", he said. In Sacramento, spokeswoman Melinda Stehr of the attorney general's office said handwriting experts confirmed the letter was a simulation of a letter sent to the San Francisco Chronicle a decade ago, which was also considered to be a hoax."Someone saw the letter and was using it as a copy." Stehr said. "It's a fake. It's a hoax". UPI.
The opening three lines of the 1978 and 1987 letters are extremely similar, with both "telling herb caen he had always been here". Why would a hoaxer, determined to convince us he was the Zodiac Killer, not only choose a previously 'debunked' letter, but imitate the wording so closely as to give the impression to investigators it was just copied? On the flip side, if the author was the Zodiac Killer, such a concern would not be a consideration. A person attempting to hoax the 1987 letter would first have to access old newspaper cuttings of Zodiac communications and handwriting to copy. If they were prepared to go to this effort, then they may as well have reproduced any Zodiac correspondence from 1969 to 1971, as opposed to selecting the 1978 letter.
The hoaxer must surely have been aware of David Toschi's perceived involvement in writing the 1978 letter and his recent retirement from law enforcement, hence the belated reference of "Tell Tochi my new plans", but nevertheless, continued on to mimic the 1978 letter anyway. The author of the 1987 letter could not have accidentally chosen to copy this letter without realizing the authenticity issues surrounding it - rather he chose it for purpose. The author of the 1987 letter could have been the author of the 1978 letter and therefore did not have to "see the (1978) letter to use it as a copy", and as a result, there was no need for imitation. The assertion by investigators that the author of the 1987 letter was somehow attempting to copy the 1978 letter would be negated in this instance, as it would be if the Zodiac Killer had authored both letters and didn't care if they looked similar in style or wording. If the 1987 letter had looked wildly different to anything mailed previously, people would say "the handwriting looks nothing like the Zodiac Killer". In this instance though, the difference was clearly not enough and therefore considered "a simulation". The December 7th 1969 and December 16th 1969 'Fairfield' letters both fell foul of this contradiction.
The Zodiac Killer implied he was responsible for the August 3rd 1969 double murder of Kathy Snoozy and Deborah Furlong in San Jose, when he mailed the November 8th 1969 'Dripping Pen' card. Two weeks later, on November 21st 1969, the San Jose Police Department were sent a warning letter threatening harm on a "widow". Then came the December 16th 1969 'Fairfield' letter which threatened "more blood" at many different locations, including a policeman in San Jose.
On July 13th 1971, a pasted card was mailed to the San Francisco Chronicle with the words "Near Monticello Shought Victims 21 ...... In The Woods Dies April". This was referencing the murder of Kathy Bilek (18) on Sunday, April 11th 1971, stabbed multiple times at Villa Montalvo in Saratoga (just west of downtown San Jose), only nine miles from the neighborhood of Monticello. This neighborhood sits next to Oak Hill Memorial Park, where Kathy Snoozy is buried. At about the same time, a 148 character cipher was received by the San Francisco Chronicle, postmarked Fairfield, California. Bearing in mind Kathy Snoozy, Deborah Furlong and Kathy Bilek were all stabbed innumerable times, disfiguring their bodies, it is rather telling that the author of the 148 character cipher and letter should threaten 3 more young people like so: "Tis the Zodiac Speacking. Why can't you stop me. I can't stop killing. Stop listening t(o) phonys. If this is not on your front page in a week I will skin 3 little kids and make a suit from the skin" and "next time I will send a patch of human skin if there is some left over".