Does a police officer have to knock on the front door of a house to interview a suspect?

As in several of the federal cases noted above, the trial court properly could characterize as reasonable the police officers' action in remaining briefly in the yard under these circumstances, notwithstanding the absence of a warrant or the failure of the officers initially to knock at the front door. (See United States v. James, supra, 40 F.3d at p. 862, fn. 4 [rejecting the notion that "police officers seeking to interview a person are always required to knock on the front door of a residence before they may approach any other public means of access to the dwelling"].) The circumstance that, while so engaged, the officers happened to observe criminal activity occurring within the residence was primarily a consequence of defendant's decision not to take any protective steps directed toward ensuring the privacy of his illegal activities.