As with the recent analyses of the 1978, 1986 and 1987 communications, we have to go beyond just the handwriting and look at the composition of the envelope, taking into consideration the stamps he applied, the format of the address and the words the author chose. In this instance, we cannot compare the address format to previously unpublished Zodiac envelopes because the communication was addressed to the Albany Times Union in New York. However, as Michael Morford correctly pointed out on the Zodiac Killer message board thread, the author of the Albany Times Union letter placed the Zodiac crosshairs in the return address section of the envelope, just like the Zodiac Killer added on his October 13th 1969, Paul Stine envelope. This was the only other time the Zodiac Killer added crosshairs on the front side of his envelope by the close of 1973. On March 8th 1981, the author would do the same on the Atlanta letter.
There is also doubt surrounding the stamps affixed to this letter - but with a fair degree of certainty we can conclude that the far left stamp was a 6c Franklin D. Roosevelt. I have superimposed it next to the black outline visible on the envelope, and it matches perfectly when sized as shown. Using the remainder of horizontal black lines, it can be reasonably argued that this envelope contained three stamps amounting to postage of 18c. The postal rate for letters (for first ounce) on August 1st 1973 was 8c, so the author had used just 2c excess over double postage. The Zodiac Killer had mailed 12 confirmed letters with Franklin D. Roosevelt stamps prior to August 1st 1973. Only three of his confirmed letters (using Tom Voigt's list of letters) contained something other than a Franklin D. Roosevelt stamp by January 29th 1974. Both the Paul Stine envelope and this communication used excessive Franklin D. Roosevelt postage.
The Albany letter, purported to have been mailed by the Zodiac Killer, also carried a cipher fashioned with striking geometric shapes. Below I have highlighted four characters in both the 148 character cipher and Albany letter code (not used by the Zodiac Killer previously) that match closely to one another. In fact, three are virtually identical. In effect, we have two consecutive suspected Zodiac communications mailed two years apart, each contained a geometric style cipher with four congruent characters, and both used the number 7 in the ciphertext to correspond with the letter A in the plaintext. The decoded 148 cipher stated "Why can't you stop me. I can't stop killing", whereas the Albany letter threatened that he was "going to start killing again". This theme continued in the May 2nd 1978 KHJ-TV Channel 9 letter, pointed out by Tom Voigt on the Albany forum thread. The author added in this latest letter that he had "decided to begin killing again", creating a fragile link between all three communications.
If we consider the crosshairs on the address side of the Albany and Stine envelope, the eccessive Franklin D. Roosevelt postage used on August 1st 1973 letter and the similarity between the two geometric ciphers shown (albeit limited), can we make a case for the May 1971 and August 1973 letters both being authored by the Zodiac Killer?