I have long believed that at least three of the four 1974 letters attributed to the Zodiac Killer, were in fact authored by the members or close affiliates of the Symbionese Liberation Army. There were four communications mailed in a 12 day period from January 29th 1974 to February 10th 1974 - and all were interwoven with one another. The Exorcist Letter (01-29-74) had a hidden message in the form of Asian-style characters, possibly decoded by Zodiac researcher Kevin Robert Brooks to spell the words "To Kill". This was extremely significant, because five days later the S.L.A. Letter was mailed on February 3rd 1974, stating "Dear Mr Editor, Did you know that the initials SLA (Symbionese Liberation Army) spell "sla", an old Norse word meaning "kill". a friend". Then, just one week after this mailing, a typed communication postmarked February 10th 1974 and addressed to the Hearst Family or FBI, was intercepted at the Burlingame, California, U.S. Postal Annex. This communication also began with "Dear" and ended with "A friend" - and the Symbionese Liberation Army (S.L.A.) was the common denominator in both.
The Exorcist Letter stated "If I do not see this note in your paper, I will do something nasty, which you know I'm capable of doing." The February 7th 1974 communication stated "I want you to put this in the news and in your paper, and if you don't you might be our next victim". This similarity would not normally be unusual in threatening letters, but for the fact that all these communications crossed over one another in just 12 days, along with the uncanny "Dear" and "A friend" in the February 3rd 1974 letter - thus far attributed to Zodiac - with the same introduction and ending attributed to the Symbionese Liberation Army on February 10th 1974. Merge this with the similar phraseology between the Exorcist Letter and the February 7th 1974 communication in such a short space of time, and you have to consider a link between all four.
One possible author of the S.L.A letter (and possibly the Exorcist letter) was Sara Jane Olson (born Kathleen Ann Soliah on January 16, 1947). She was a member of the Symbionese Liberation Army in the 1970s. She grew up in Palmdale, California, the daughter of Norwegian-American parents, Elsie Soliah (née Engstrom) and Palmdale High School English teacher and coach Martin Soliah. Engström, Engstrøm and Engstrom are surnames of Swedish and Norwegian origin. Was she responsible for authoring the S.L.A letter on February 3rd 1974, one or two days before the kidnapping of Patricia Hearst?
The other was Camilla Christine Hall, whose parents, George Fridolph Hall (1908-2000) and Lorena Daeschner Hall (1911-1995), worked at Gustavus Adolphus College in Saint Peter, Minnesota from 1938-1952. In addition, her father was a minister in the Augustana Evangelical Lutheran Church, Lutheran Church in America, and later the Evangelical Lutheran Church in America. Her mother, Lorena (Daeschner) Hall, helped found Gustavus Adolphus College's Art Department and served as the department head.
Camilla Hall attended Gustavus Adolphus College in St. Peter, Minnesota. She transferred to the University of Minnesota after her freshman year at Gustavus. Hall attended special lectures, exhibits, and concerts at the University. On June 10, 1967, Hall graduated with a humanities degree from the University of Minnesota. Gustavus Adolphus College is a private, coeducational liberal arts college in St. Peter, Minnesota, United States. A four-year, residential institution, Gustavus Adolphus College was founded in 1862 by Swedish Americans and is affiliated with the Evangelical Lutheran Church in America. The college retains its Swedish and Lutheran heritage. Gustavus is guided by five core values: excellence, community, justice, service, and faith.
Camilla Hall's blonde hair and fair complexion caused people to remark of her Scandinavian ancestors.
Since the author of the February 7th 1974 communication was likely a woman - and bearing in mind the Scandinavian connection to the S.L.A. Letter - it has to be considered that one of these female members of the Symbionese Liberation Army, could be the author of the S.L.A. Letter - and quite possibly the Exorcist Letter too.