The Zodiac Killer (or copycat) mailed a menacing postcard to Dr, Edward Adams in Orinda, California (near Walnut Creek) on October 12th 1970 stating "The Zodiac is going to change the way of committing murders. I shall announce when I shall commit my murders, The Adamses are Next you taught me to Mean it. ADAMS YOU ARE NEXT. ZODIAC."
As shown on the ZodiacKillerSite forum, Dr. Edward Adams and his wife featured in the newspapers prior to this threatening communication, so it is perfectly feasible that the author of the San Jose letter and code had identified his target in the days, weeks or months prior to the November 21st 1969 correspondence. Because of the nature of the redacted text, it appears that this letter was addressed specifically to a titled officer (possibly a Sergeant or Chief) of the San Jose Police Department. Bearing in mind the target of a 'widow' mentioned in the text, the author may be referring to a newspaper article involving the death of her husband, featuring commentary by the police official the letter is addressed to. The officer's name could be any number of characters in length depending on the title he holds, with the widow's surname just 5 or 6 characters in length.
Was the widow a prominent member of society as suggested by AK Wilks, possibly a policewoman or politician, titled like Dr. Edward Adams. On December 16th 1969 the Zodiac Killer had set his sights on a cop or "government life".
The phone call was received on Friday December 19th 1969 by San Jose police dispatcher Shirley Searcy.
The disputed December 7th and 16th 1969 Fairfield letters (not published in the newspapers) both contained threats to murder cops for the first time, with the latter threatening to murder one policeman in San Jose. Three days later, this call to a San Jose Highway Patrol station threatening to murder police is remarkable timing. Was the caller responsible for both Fairfield letters - and more importantly - was it the Zodiac Killer?
I have searched high and low for the identity of this woman, but without a newspapers.com account to aid in the search I have failed to make any inroads. The author of the San Jose letter (if Zodiac) certainly didn't need a valid reason to target anybody, as shown by his murderous assault in the Bay Area, but the identity of the 'widow' could help to add legitimacy to both Fairfield letters mailed in December, dependent on her profession or previous relationship. The November 21st, December 7th and December 16th communications all contained short codes, the amateurish nature of which has led many to believe these three letters are the work of an impostor. But these features may actually bolster the argument for Zodiac involvement, as all three were never attempting to mimic the previously polished 408 and 340 cipher, which somebody attempting to mimic the Zodiac would surely have done.
UPDATE: THE DRIPPING PEN CARD AND SAN JOSE CONNECTION
THE STORY OF SAN JOSE