CA Health & Safety Code Section 11704

(a)

A person who knowingly participates in the marketing of illegal controlled substances within this state is liable for civil damages as provided in this division. A person may recover damages under this division for injury resulting from an individual’s use of an illegal controlled substance.

(b)

A law enforcement officer or agency, the state, or a person acting at the direction of a law enforcement officer or agency or the state is not liable for participating in the marketing of illegal controlled substances, if the participation is in furtherance of an official investigation.