William Otto Weissich was born on October 31, 1920 in San Francisco, California and grew up in Mill Valley where his family had settled in 1907. He attended Marin County schools and graduated from the University of San Francisco where he also obtained his law degree from the School of Law. During World War II he served in the U.S. Army Reserve. In December 1946 he was admitted to the California State Bar and entered into private practice in Marin. In 1950 he joined the Marin County District Attorney’s Office as a Deputy District Attorney. When District Attorney Richard M. Sims was appointed to the Marin County Municipal Court bench in 1953, Weissich was appointed District Attorney by the Marin County Board of Supervisors to serve out Sims’ remaining term. Thereafter Weissich was elected to serve as District Attorney and held that position until 1960 when he resigned and entered private practice again. During his tenure with the Marin County District Attorney’s Office he gained a reputation as a fearless, hard-hitting, and relentless prosecutor who in either victory or in defeat was neither overly elated nor unduly discouraged.
In 1955, Weissich prosecuted and convicted Malcolm Schlette for the crime of arson. Malcolm Schlette was sentenced to state prison where he served a lengthy prison term. On November 18, 1986, several years after he left the District Attorney’s Office, as William Weissich sat behind his desk in his private law office in San Rafael, Malcolm Schlette entered Weissich’s office. At point blank range, Schlette fired a handgun at Mr. Weissich shooting Weissich at least twice in the forehead and upper chest. Mr. Weissich died instantly. Schlette fled the crime scene. Upon report of the shooting, Schlette was surrounded in his escape vehicle by Marin County police officers shortly thereafter. Schlette thereupon committed suicide. A typed note dated November 17, 1986, and signed by Schlette was found in his apartment after the murder. In the note, Schlette indicated that his “final act” of revenge was to perform “acts of violence” on five people he believed were responsible for sending him to prison. One of those named persons was District Attorney William O. Weissich, the man who had prosecuted and convicted Schlette for arson 31 years before.
On June 10, 2005, William O. Weissich’s name was added to Prosecutors Memorial at the Ernest F. Hollings National Advocacy Center on the campus of the University of South Carolina in Columbia, South Carolina. This memorial was established by the National District Attorneys Association in 2004 to honor prosecutors killed in the line of duty. Because William Weissich was tragically murdered as the result of his work performed in the line of duty as the Marin County District Attorney, he was truly deserving of having his name included on the memorial.