Pen. Code, § 11471

(a) Except as authorized by this article, no government entity, and no service provider acting at the request of a government entity, shall interrupt a communication service for either of the following purposes:

(1) To prevent the communication service from being used for an illegal purpose.

(2) To protect public health, safety, or welfare.

(b) A government entity may interrupt a communication service for a purpose stated in subdivision (a) in any of the following circumstances:

(1) The interruption is authorized by a court order pursuant to Section 11473.

(2) The government entity reasonably determines that (A) the interruption is required to address an extreme emergency situation that involves immediate danger of death or great bodily injury, (B) there is insufficient time, with due diligence, to first obtain a court order under Section 11473, and (C) the interruption meets the grounds for issuance of a court order under Section 11473. A government entity acting pursuant to this paragraph shall comply with Section 11475.

(3) Notwithstanding Section 591, 631, or 632, or Section 7906 of the Public Utilities Code, a supervising law enforcement official with jurisdiction may require that a service provider interrupt a communication service that is available to a person if (A) the law enforcement official has probable cause to believe that the person is holding hostages and is committing a crime, or is barricaded and is resisting apprehension through the use or threatened use of force, and (B) the purpose of the interruption is to prevent the person from communicating with anyone other than a peace officer or a person authorized by a peace officer. This paragraph does not authorize the interruption of communication service to a wireless device other than a wireless device used or available for use by the person or persons involved in a hostage or barricade situation.