Can a warrantless search of a person's home be conducted without a warrant?

Here, the trial court found that the warrantless search in this case was permissible under both the protective sweep and community caretaking exceptions to the warrant requirement. On appeal, we review the trial court's ruling as a mixed question of law and fact; we must accept the trial court's factual findings so long as they are supported by substantial evidence, but independently determine the applicable law and apply constitutional principles to the facts. (People v. Woods (1999) 21 Cal.4th 668, 673-674.)

A. Protective Sweep

In accordance with the protective sweep exception to the warrant requirement, police officers who make an in-home arrest may, "as [a] precautionary matter and without probable cause," constitutionally search the house to ensure that it is free from other suspects who may wish to do them harm. (Maryland v. Buie (1990) 494 U.S. 325 [in home arrest].) There is a split of authority as to whether the protective sweep exception applies where, as here, officers arrest or detain a suspect outside the home. (See People v. Celis (2004) 33 Cal.4th 667, 678-679 (Celis), & cases cited therein.) There is no question, however, that the exception is inapplicable unless there are "articulable facts," and rational inferences therefrom, to support a reasonable suspicion on the officers' part that the area to be swept harbors a person who poses a danger to them or others. (Id. at pp. 679-680.) Because there were no such "articulable facts" present in this case, we conclude that the protective sweep exception is inapplicable on that basis, without reaching the broader issue of whether the exception applies to an out-of-home arrest or detention. (See id. at p. 679.)