Grand Jury law is embedded in the Penal Code, all in a section identified as Part 2, Title IV beginning with section 888 which states: A grand jury is a body of persons to inquire of public offenses committed or triable within the county.  One grand jury in each county shall be charged and sworn to investigate matters of civil concern.

This Code succinctly sets forth the two functions of a grand jury in California.  The California county grand jury's authority has been upheld by both case law and Attorney General Opinions.