An article from ABC News in 2003: "The lab has found a partial DNA "fingerprint" on one of the envelopes, but not enough for definitive matching. However, a Primetime investigation prompted the discovery of three envelopes that offer new hope. The envelopes (July 31st 1969) were thought to have been lost, but an anonymous Primetime source — a long-retired investigator — found them, in mint condition, during a search of his personal files and turned them over to the San Francisco police".
Experts very quickly determined the 1987 letter was mailed by a hoaxer. "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". When they made this determination, they clearly didn't have the July 31st 1969 Vallejo Times-Herald envelope at their disposal, so they could compare it to the October 28th 1987 envelope. If they had, they may very well have come to a different conclusion. The Zodiac Killer wrote 'Vallejo Times' in his letters when he addressed the Chronicle and Examiner on July 31st 1969 (which were made public), but his envelope to the Vallejo newspaper contained the full name of 'Vallejo Times Herald'. An envelope not made public prior to October 28th 1987. Yet the recent 1987 envelope contained the full title of 'Vallejo Times Herald', just like the unpublished 1969 Vallejo envelope.
If you compare the now available July 31st 1969 Vallejo Times-Herald envelope, with the October 28th 1987 Vallejo Times-Herald envelope, the similarity is noticeable. How could a hoaxer mimic the 1969 Vallejo envelope so closely if he had never laid eyes on it. The same words and amount of words (and abbreviations) are used in both, with no commas or full stops in either address. The dominant alphabetical V is present on both, with a distinct right leaning slant extending over the "a" of Vallejo. Up to October 28th 1987, these were the only two communications ever mailed to the Vallejo Times-Herald from either Zodiac, or a supposed copycat of Zodiac. If the July 31st 1969 Vallejo Times-Herald envelope was never made public prior to October 28th 1987, I suggest that this recent Halloween offering should be declared genuine Zodiac Killer correspondence. This is the best image available of the 1987 envelope. There are two March 29th 1985 issue date 22c stamps of Flag Over Capitol on the 1987 envelope. The May 6th 1986 'Zodiac' envelope contains one smaller Flag Over Capitol stamp.