Cipher message to Zodiac

On October 23, 1969, the San Francisco Examiner published an article about the ongoing hunt for the Zodiac killer. This enciphered “message to Zodiac” appeared in the article:

The article was published after the 408-character cryptogram was solved, and before the 340-character cryptogram was mailed.

Using a simple observation, you can easily solve the Examiner’s cryptogram (if you want to skip ahead to the solution, click here). The cryptogram has only 44 characters, and 33 of them are unique. With so few repeated characters, many possible plain texts can fit. For example, if you feed the cryptogram to zkdecrypto, it yields this plaintext:


This solution looks a lot like English text, but is the wrong solution. This cryptogram would have been very difficult to solve without applying the simple observation. Do you know of a way to solve it without knowing the trick?

(Thanks to Deb for uncovering the article)

UPDATE Apr 24, 2013: Here is an excerpt from the book The Cases That Haunt Us with more details on the origin of the Examiner’s cryptogram: