The only two communications tested in the San Francisco Police Department DNA report for cells, from 1974 onwards, were the Exorcist letter and 1978 letter. Therefore, these were the only letters that could reasonably have matched for DNA. Two of the other 1974 communications were not processed for DNA, and the SLA letter wasn't even listed as a "suspected Zodiac correspondence". If Alan Keel believes the 1978 letter to be a "forgery" along with one of the 1974 letters, it is unlikely to be the Exorcist letter. To the best of my knowledge, the envelopes to the April 20th 1970 (13-Symbol cipher) and April 28th 1970 (Dragon card) were not published in any newspapers. These were the only two confirmed Zodiac envelopes to carry the address of San Fran (dot) Chronicle prior to January 29th 1974. Below is a comparison from these two envelopes and the Exorcist letter. The author of the Exorcist letter (if a hoaxer) had the option to copy the envelope published in the San Francisco Chronicle on November 16th 1970, but chose not to. The spacing and composition may suggest one author. If you believe that the April 20th 1970 and April 28th 1970 letters to be the Zodiac Killer, then it's probably reasonable to conclude the Exorcist letter (and envelope) was composed by the Zodiac Killer as well.
Therefore, if only two letters matched in DNA, the only possible option is the Exorcist letter and 1978 letter, making both genuine Zodiac communications. Especially when you consider the Exorcist letter was the only communication processed for DNA (and cells were found). This suggests that Zodiac did lick his envelopes and/or stamps. It also suggests that David Toschi is not responsible for writing the 1978 letter, because if he did, he would also be the author of the Exorcist letter, April 20th 1970 letter and April 28th 1970 letter, based on the argument of Alan Keel and the findings above.
THE PHANTOM ZODIAC LETTER ON JULY 8TH 1974 [PART TWO]