Despite the 340 cipher being unbroken in 1971, both ciphers were referring to Eric Weill, ultimately found responsible for the Jim Dunbar hoax. The phonys Zodiac was referring to in his 148 character cipher were Eric Weill and Karl Francis Werner, the latter of which, had recently been arrested and questioned by detectives for the murder of Kathy Bilek on April 11th 1971 in Saratoga, and the murders of Kathie Snoozy & Debra Furlong on August 3rd 1969 in San Jose, which the Zodiac Killer had long claimed were his victims. He would compound matters by adding Kathy Bilek to his victim total when he mailed the Monticello card on July 13th 1971.
On December 7th 1969, the same day somebody impersonated the Jim Dunbar caller when phoning an Oklahoma radio station, another Zodiac letter arrived at the San Francisco Chronicle impersonating the Jim Dunbar caller, stating "I Just Need Help" and "I Will Turn Myself In". Bearing in mind that this letter pre-empted the Melvin Belli letter on December 20th 1969 that thrice pleaded "please help me", there was a more than a good chance that the 38 character code that accompanied this letter, concealed a message about Melvin Belli and the hoax phone call to the Jim Dunbar Show. There would also be a high probability that the Zodiac Killer would use a recent newspaper article for his hidden 38 character message, continuing this theme.
It is the headline text accompying the Melvin Belli picture that I considered the Zodiac Killer probably responded to, just like he did when composing his 340 and 148 character ciphers. I worked out a viable message in the Z38 that read "TRYING TIMES. SO I NEED APPOINTMENT TO GET HELP". This wasn't the "good times" Zodiac was used to, but the formulated message is in keeping with the rhetoric displayed in the Melvin Belli letter on December 20th 1969, and with the headline text in the Los Angeles Times newspaper. I am not claiming this is the answer to the 38 character code, but it does conform to the standards of cryptology, with the coded message and accompanying writing in the letter congruent with the story in the Los Angeles Times newspaper on October 23rd 1969.
The newspaper article (edited for conciseness below) was published in the Los Angeles Times on December 16th 1969, a matter of hours before the second Fairfield letter was mailed with an afternoon postmark. The opening line of Zodiac's letter began with "I just want to tell you this state is in trouble", which is synonymous with the newspaper article that headlined with "State Furnishes List of Murders Similar to 7 Slayings Here", as well as the opening paragraph of the article that adds "State officials have provided Los Angeles police with details of 30 unsolved murders", and the sub-headline of "All Murders Logged by State".
The Zodiac Killer would counter the list provided by state officials with a list of his own. At the foot of his December 16th 1969 Fairfield letter he would give us a list of locations and the number of police he promised to kill in each city (38 in total). This would develop in later communications, in which the Zodiac Killer gave us a list of "society offenders" to be targeted when he plagiarized verses from The Mikado, a Savoy comic opera crafted by Sir William Schwenck Gilbert and Sir Arthur Seymour Sullivan, released in London on March 14th 1885.
Government Official means any officer, employee or other individual acting in an official capacity for a Governmental Authority or agency or instrumentality thereof (including any state-owned or controlled enterprise). This may explain the Zodiac Killer's use of the phrase "government life" in his letter. It appeared that the second Fairfield letter was specifically responding to this newspaper article (see below) - both of which corresponded to one date. Susan Denise Atkins (21), one of six persons charged with the Tate-LaBiaca murders, provided information to police where they could find items of disposed bloody clothing related to the Cielo Drive attack, detailed in the article as "A station spokesman said the clothes, stained with what appeared to be blood and knotted in a bundle were turned over to police". I have highlighted these below in reference to the Zodiac Killer's statement of "look for more blood" in the Fairfield letter. The police were effectively dispatched to look for items of clothing stained with blood in the Tate-LaBianca slayings, to which Zodiac suggested there would be more blood in future for police to find.