California Government Code Section 821.6 - Interpretation
Government Code section 821.6, creates an immunity caused by "instituting or prosecuting any judicial or administrative proceeding."
In Johnson v. City of Pacifica (1970) 4 Cal. App. 3d 82 84 Cal. Rptr. 246, the plaintiff alleged the officers had negligently, but not maliciously, instituted proceedings.
The court held the concluding language of section 821.6, which specifies the immunity applies "even if he acts maliciously and without probable cause," implied the immunity also attached if the acts were not malicious. (Johnson, at p. 87.)
Government Code section 821.6, covers injuries caused by "instituting or prosecuting any judicial or administrative proceeding."