Forced Entry to Make Arrest Allowed after Notice,

and Refusal. (a) To make an arrest, whether with or without a warrant, a peace officer may break open the door or window of any house in which the person to be arrested is, or in which the officer has reasonable cause for believing him to be, if, after giving notice of his authority and purpose, he is refused admittance. (b) A peace officer who has witnessed the commission of an offense may pursue the offender into any ship, plane, building, or grounds. NOTE: Section 20.50 continues the substance of former §§ 844 and 855. See also Cal. Pen. Code § 844. See generally B. Witkin, California Criminal Procedure, Procedure Before Trial, § 111 (1063, Supp. 1973). It should be noted that case law authorized practical exceptions to the announcement requirement. That is, noncompliance may be excused where specific facts known to the officer before his unannounced entry are sufficient to support his good-faith belief that compliance would increase his peril, frustrate arrest, or permit the destruction of evidence. See, e.g., Parsley v. Superior Court, 9 C.3d 934, 109 Cal. Rptr. 563, 513 P.2d 611(1973).