West's Ann.Cal.Welf. & Inst.Code § 5150
When any person, as a result of mental disorder, is a danger to others, or to himself or herself, or gravely disabled, a peace officer, member of the attending staff, as defined by regulation, of an evaluation facility designated by the county, designated members of a mobile crisis team provided by , or other professional person designated by the county may, upon probable cause, take, or cause to be taken, the person into custody and place him or her in a facility designated by the county and approved by the State Department of Mental Health as a facility for 72-hour treatment and evaluation.
Such facility shall require an application in writing stating the circumstances under which the person's condition was called to the attention of the officer, member of the attending staff, or professional person, and stating that the officer, member of the attending staff, or professional person has probable cause to believe that the person is, as a result of mental disorder, a danger to others, or to himself or herself, or gravely disabled. If the probable cause is based on the statement of a person other than the officer, member of the attending staff, or professional person, such person shall be liable in a civil action for intentionally giving a statement which he or she knows to be false.
_ In re Qawi, Cal.Rptr.3d 780 Cal.,2004.