Cal. Penal Code § 136.1

(a) Except as provided in subdivision (c), a person who does any of the following is guilty of a public offense and shall be punished by imprisonment in a county jail for not more than one year or in the state prison: (1) Knowingly and maliciously prevents or dissuades a witness or victim from attending or giving testimony at a trial, proceeding, or inquiry authorized by law. (2) Knowingly and maliciously attempts to prevent or dissuade a witness or victim from attending or giving testimony at a trial, proceeding, or inquiry authorized by law. (3) For purposes of this section, evidence that the defendant was a family member who interceded in an effort to protect the witness or victim shall create a presumption that the act was without malice.

(b) Except as provided in subdivision (c), a person who attempts to prevent or dissuade another person who has been the victim of a crime or who is witness to a crime from doing any of the following is guilty of a public offense and shall be punished by imprisonment in a county jail for not more than one year or in the state prison: (1) Making a report of that victimization to a peace officer, a state or local law enforcement officer, a probation, parole, or correctional officer, a prosecuting agency, or a judge. (2) Causing a complaint, indictment, information, or probation or parole violation to be sought and prosecuted, or assisting in the prosecution thereof. (3) Arresting or causing or seeking the arrest of a person in connection with that victimization.

(c) A person doing any of the acts described in subdivision (a) or (b) knowingly and maliciously under any one or more of the following circumstances, is guilty of a felony punishable by imprisonment in the state prison for two, three, or four years under any of the following circumstances: (1) If the act is accompanied by force or by an express or implied threat of force or violence, upon a witness, victim, or any third person or the property of a victim, witness, or any third person. (2) If the act is in furtherance of a conspiracy. (3) If the act is committed by a person who has been convicted of a violation of this section, a predecessor law, a federal statute, or a statute of any other state that, if the act prosecuted was committed in this state, would be a violation of this section. (4) If the act is committed by a person for pecuniary gain or for any other consideration acting upon the request of any other person. All parties to the transaction are guilty of a felony.

(d) A person attempting the commission of an act described in subdivision (a), (b), or (c) is guilty of the offense attempted without regard to success or failure of the attempt. The fact that no person was injured physically, or in fact intimidated, is not a defense against prosecution under this section.

(e) This section does not preclude the imposition of an enhancement for great bodily injury if the injury inflicted is significant or substantial.

(f) The use of force during the commission of an offense described in subdivision (c) shall be considered a circumstance in aggravation of the crime in imposing a term of imprisonment under subdivision (b) of Section 1170.