The SLA letter was postmarked "U.S. Postal Service, CA 913 PM 3 FEB 1974" - the letter began with the word "Dear" and signed off with the rather tame "a friend". Zodiac researchers, understandably don't want to believe the letter was mailed on February 3rd 1974, because they have a vested interest going back decades, including printed material based on a 'Zodiac Killer' responding to the kidnapping of Patricia Campbell Hearst by mailing this letter on or around February 14th 1974, despite the fact nothing in the SLA letter refers to the kidnapping. So, just for arguments sake, let us assume the Zodiac Killer mailed the letter on February 14th 1974, signing off the letter with "a friend".
On February 10th 1974, just 4 days prior to the SLA letter, a typewritten letter in a white envelope was mailed to the Hearst family, postmarked "U.S. Postal Service, CA 940 PM 10 FEB 1974", bearing the typewritten address "R.A Hearst Family, 233 W. Santa Inez Ave, Hillsborough, Cal, 94010??". It read [corrected for spelling] :
Dear Hearst Family,
I am white, and I am sorry I joined the people who have your daughter. I saw her Wednesday and she was alright. She is brave and beautiful and innocent. Don't let her marry that Weed man. He talked to our brass last month and said how to set it up. He said if he marries her, he must have enough money to hold up his head. He got his idea from Miss Angela Davis, who gives orders and ideas to our brass.
I am so ashamed to belong I am trying to get out easy, but God help me if they find out I write this. They are animals, but I don't think they will hurt her. God bless you, and God forgive me.
The 'Hearst Family' letter may have been authored by Sara Jane Olson (born Kathleen Ann Soliah), who could also be responsible for the SLA letter mailed from Los Angeles (913) just a week earlier, on February 3rd 1974. The "Old Norse" element of the letter drawn from her Norwegian-American ancestry. Both communications began with "Dear" and ended with "a friend".
The 'Hearst Family' typewritten letter and envelope can be seen below, postmarked February 10th 1974, accompanied by a notation of "For FBI or Family" [corrected].