Opinion
WERDEGAR, J.
Police in this case looked through a window and observed defendant packaging cocaine in his home. The officers made this [828]*828observation while standing in defendant’s side yard, a place they had no legal right to be. The Court of Appeal held the police violated defendant’s right to be free of unreasonable searches and seizures under the Fourth Amendment to the United States Constitution and, accordingly, concluded the trial court erred in denying defendant’s motion to suppress the evidence against him. We affirm.
Facts
On June 26, 1997, police received an anonymous complaint of a “loud party disturbance” at defendant Cayetano Calderon Camacho’s house. Officers Wood and Mora, responding to the complaint, arrived at defendant’s home around 11:00 p.m. Officer Wood testified that, on arrival, he heard no noise upon exiting his patrol car. Approaching defendant’s home, the officers heard no excessive noise. Officer Wood testified, rather, that he heard merely an unidentifiable “audible noise,” one that was neither loud, disturbing nor violative of the city’s noise ordinance.
The officers did not knock on the front door. Instead, while Officer Wood remained on the front lawn, Officer Mora walked into the side yard of the single-story house. The officers did not have a warrant. The side yard was an open area covered in grass. No fence, gate or shrubbery suggested entrance was forbidden. Neither, however, did anything indicate the public was invited to enter; there was neither a path nor a walkway, nor was there an entrance to the home accessible from the side yard. An opaque brick wall, about six feet nine inches high, blocked entrance into the backyard. A cement block wall of similar height marked the property line between defendant’s side yard and the home of his immediate neighbor.
Defendant’s home was set back about 20 feet from the public sidewalk. About 20 feet from the front of the house and 40 feet from the sidewalk, Officer Mora came upon a large side window. The window is visible from the public street or sidewalk, but the inside of the room is not. The neighbor on that side of the house would have difficulty seeing into the window because of the high cement block wall separating the two homes. The yard had no exterior lighting.
The window, which was open a few inches, had no blinds, curtains or other covering. Officer Mora, standing in the darkened side yard outside the window, heard music coming from the stereo inside the room, although the music was not loud. A red light bulb dimly lit the room. Returning to the front of the house, Mora reported to Officer Wood that he had seen a man in a room but was unsure whether the man was committing a crime. The two [829]*829officers proceeded together back through the side yard to the window. There, Officer Wood saw defendant, sitting with his back to the window, manipulating some clear plastic baggies. Wood saw several baggies with a white powdery substance on the bed and dresser in the room, as well as a cellular phone and a pager. The officers retreated to the front of the house, called for backup, returned to the side yard and entered the house through the window, whereupon they arrested defendant.
Defendant was charged with possession of a controlled substance (cocaine) for sale. (Health & Saf. Code, § 11351.) He moved to suppress the evidence, relying on Lorenzana v. Superior Court (1973) 9 Cal.3d 626 [108 Cal.Rptr. 585, 511 P.2d 33] (Lorenzana). The trial court denied the motion to suppress, observing: “Well, I think the key to the analysis, the important key, and that’s using Lorenzana, is the expectation of privacy. HO And I don’t think there can be an expectation of privacy on the initial threshold because, in looking at this window, even with the lights on, to me, an expectation of privacy is what the defendant in Lorenzana had because he had his window really covered and the officer had to get within five to six inches and look through a little, tiny slot. In other words, the window was opaque.
“Here, the window was closed, pretty much. There is nothing covering up the defendant’s activity, which is clearly drug-type activity. And the only other question is the intrusion issue. And I don’t know whether it’s close or not, but the officer was on a legitimate call for a legitimate reason.
“And I think you can probably argue, explicitly, they had a right to try to look to find the music. So I think the key to the defendant’s expectation of privacy—I think he gave it away by at least not having the blinds closed. ft[] If, in fact, the blinds were closed—I would look at it differently—and the officer had to go up to the window and peer down and look through a one-inch opening. Just walking by this window you can see fairly well
After his suppression motion was denied, defendant pleaded guilty and appealed. (Pen. Code, § 1538.5, subd. (m).) The Court of Appeal reversed.
Discussion
The Fourth Amendment provides “[t]he right of the people to be secure in their persons, houses, papers and effects, against unreasonable searches and seizures, shall not be violated . . . .” (U.S. Const., 4th Amend.) This guarantee has been incorporated into the Fourteenth Amendment to the federal Constitution and is applicable to the states. (See Mapp v. [830]*830Ohio (1961) 367 U.S. 643 [81 S.Ct. 1684, 6 L.Ed.2d 1081] [federal exclusionary rule applicable to the states].) A similar guarantee against unreasonable government searches is set forth in the state Constitution (Cal. Const., art. I, § 13) but, since voter approval of Proposition 8 in June 1982, state and federal claims relating to exclusion of evidence on grounds of unreasonable search and seizure are measured by the same standard. (In re Tyrell J. (1994) 8 Cal.4th 68, 76 [32 Cal.Rptr.2d 33, 876 P.2d 519]; In re Lance W. (1985) 37 Cal.3d 873, 886-887 [210 Cal.Rptr. 631, 694 P.2d 744].) “Our state Constitution thus forbids the courts to order the exclusion of evidence at trial as a remedy for an unreasonable search and seizure unless that remedy is required by the federal Constitution as interpreted by the United States Supreme Court.” (In re Tyrell J., supra, at p. 76) 1
In reviewing the action of the lower courts, we will uphold those factual findings of the trial court that are supported by substantial evidence. The question of whether a search was unreasonable, however, is a question of law. On that issue, we exercise “independent judgment.” (People v. Leyba (1981) 29 Cal.3d 591, 597 [174 Cal.Rptr. 867, 629 P.2d 961]; People v. Memro (1995) 11 Cal.4th 786, 838 [47 Cal.Rptr.2d 219, 905 P.2d 1305].) Because the officers lacked a warrant, the People bore the burden of establishing either that no search occurred, or that the search undertaken by the officers was justified by some exception to the warrant requirement. (See Vale v. Louisiana (1970) 399 U.S. 30, 34 [90 S.Ct. 1969, 1971-1972, 26 L.Ed.2d 409]; People v. Rios (1976) 16 Cal.3d 351, 355 [128 Cal.Rptr. 5, 546 P.2d 293].)
The “ultimate standard set forth in the Fourth Amendment is reasonableness” (Cady v. Dombrowski (1973) 413 U.S. 433, 439 [93 S.Ct. 2523, 2527, 37 L.Ed.2d 706]), and, after Katz v. United States (1967) 389 U.S. 347 [88 S.Ct. 507, 19 L.Ed.2d 576] (Katz), we ask two threshold questions. First, [831]*831did the defendant exhibit a subjective expectation of privacy? Second, is such an expectation objectively reasonable, that is, is the expectation that one society is willing to recognize as reasonable? (Bond v. United States (2000) 529 U.S. 334, 337-338 [120 S.Ct. 1462, 1464-1465, 146 L.Ed.2d 365, 370] (Bond); California v. Ciraolo (1986) 476 U.S. 207, 211 [106 S.Ct. 1809, 1811-1812, 90 L.Ed.2d 210] (Ciraolo).) Although the trial court’s finding on the first point is obscure, we conclude defendant exhibited a subjective expectation of privacy, in that he did not expect people to be intruding onto his private property at 11:00 p.m. and looking into his windows. (Cf. Bond, supra, 529 U.S. at p. 337 [120 S.Ct. at p. 1464, 146 L.Ed.2d at p. 369] [“physically invasive inspection is simply more intrusive than purely visual inspection”].) We thus turn to address whether, under all the facts, defendant’s expectation of privacy was objectively reasonable.
“At the risk of belaboring the obvious, private residences are places in which the individual normally expects privacy free of governmental intrusion not authorized by a warrant, and that expectation is plainly one that society is prepared to recognize as justifiable.” (United States v. Karo (1984) 468 U.S. 705, 714 [104 S.Ct. 3296, 3303, 82 L.Ed.2d 530].) Indeed, “the ‘physical entry of the home is the chief evil against which the wording of the Fourth Amendment is directed.’ ” (Payton v. New York (1980) 445 U.S. 573, 585 [100 S.Ct. 1371, 1379, 63 L.Ed.2d 639], quoting United States v. United States District Court (1972) 407 U.S. 297, 313 [92 S.Ct. 2125, 2134, 32 L.Ed.2d 752].) A central principle of the Fourth Amendment is that a person may “retreat into his own home and there be free from unreasonable governmental intrusion.” (Silverman v. United States (1961) 365 U.S. 505, 511 [81 S.Ct. 679, 683, 5 L.Ed.2d 734, 97 A.L.R.2d 1277].)
Balanced against this solicitude for privacy in the home is the need for effective law enforcement. Thus, “[t]he Fourth Amendment protection of the home has never been extended to require law enforcement officers to shield their eyes when passing by a home on public thoroughfares. Nor does the mere fact that an individual has taken measures to restrict some views of his activities preclude an officer’s observations from a public vantage point where he has a right to be and which renders the activities clearly visible. [Citation.] ‘What a person knowingly exposes to the public, even in his own home . . . , is not a subject of Fourth Amendment protection.’ ” (Ciraolo, supra, 476 U.S. at p. 213 [106 S.Ct. at pp. 1812-1813], quoting Katz, supra, 389 U.S. at p. 351 [88 S.Ct. at p. 511].)
Officers Wood and Mora were not, of course, standing on a public thoroughfare when they observed defendant packaging cocaine; they were in his yard. Nevertheless, their observations would not constitute a search (in [832]*832the constitutional sense) and thus not violate the Fourth Amendment if they were standing in a place where they otherwise had a right to be. (Ciraolo, supra, 476 U.S. at p. 213 [106 S.Ct. at pp. 1812-1813].) This case thus turns on whether Officers Wood and Mora were legally entitled, under all the circumstances, to be in defendant’s side yard.
We addressed this precise point in Lorenzana, supra, 9 Cal.3d 626. In that case, the police, responding to an anonymous tip about drug dealing at the defendant’s home, went into the side yard of his house. As here, the side yard was an otherwise barren, grass-covered patch of land bearing neither a fence, gate, landscaping nor a path to indicate that the public was expressly or implicitly invited in. Unlike in this case, when the investigating police officer in Lorenzana entered the side yard, he found the window largely obscured by drawn curtains. Undeterred, he crouched down and looked through a two-inch gap between the curtains and the windowsill, but could not see into the room until his face was five or six inches from the window. The officer watched and listened for 15 minutes; in this manner, he acquired evidence of drug dealing and made the arrest.
In issuing a writ to reverse the denial of a suppression motion, Justice Tobriner, writing for the court, relied principally on the fact the officer had trespassed on the defendant’s property and thus, when he observed the evidence of criminality, he was not standing on property that had been expressly or impliedly opened to the public. “[Past cases] clearly demonstrate the salutary rule of law that observations of things in plain sight made from a place where a police officer has a right to be do not amount to a search in the constitutional sense. On the other hand, when observations are made from a position to which the officer has not been expressly or implicitly invited, the intrusion is unlawful unless executed pursuant to a warrant or one of the established exceptions to the warrant requirement.” (.Lorenzana, supra, 9 Cal.3d at p. 634, fn. omitted.)
“[A] resident of a house [may] rely justifiably upon the privacy of the surrounding areas as a protection from the peering of the officer unless such residence is ‘exposed’ to that intrusion by the existence of public pathways or other invitations to the public to enter upon the property. This justifiable reliance on the privacy of the non-common portions of the property surrounding one’s residence thus leads to the particular rule that searches conducted without a warrant from such parts of the property always are unconstitutional unless an exception to the warrant requirement applies.” (Lorenzana, supra, 9 Cal.3d at p. 638, italics omitted; see 1 LaFave, Search and Seizure (3d ed. 1996) Protected Areas and Interests, § 2.3(c), pp. 480 & fn. 65, 485-486 [citing Lorenzana with approval].)
[833]*833Defendant argues Lorenzana controls this case, while respondent and the dissent contend Lorenzana is distinguishable on its facts. Although we find slight factual differences between Lorenzana and the instant case, none implicate the core holding of Lorenzana, to wit, that observations by law enforcement officers intrude on a person’s reasonable expectation of privacy if made from private property onto which neither the public nor the police has been invited, and in circumstances wherein police lack a legal justification for being on the property.
Respondent and the dissent emphasize that, unlike in Lorenzana, Officers Wood and Mora did not peer into a small opening or aperture in the curtains to intrude on defendant’s privacy. Instead, defendant’s rather large (four- by eight-foot) window was completely uncovered, so that any person in the side yard could easily have viewed his unlawful activity. From this circumstance, respondent and the dissent would have us conclude defendant failed to exhibit an expectation of privacy that was reasonable.
Although it is true the officer in Lorenzana was forced to peer through a small opening between the drawn curtains and the windowsill to observe the defendant’s illegal activity, our decision in that case did not turn on the surreptitious nature of the officer’s observation. Instead, Lorenzana identified a broader proposition: a warrantless search cannot be justified by police observations “made from a position to which the officer has not been expressly or implicitly invited.” (Lorenzana, supra, 9 Cal.3d at p. 634.)
None of the cases cited by respondent support a contrary conclusion. All either involve the police making observations from a public vantage point (e.g., People v. Berutko (1969) 71 Cal.2d 84, 88 [77 Cal.Rptr. 217, 453 P.2d 721] (Berutko) [front of apartment building]; United States v. Hersh (9th Cir. 1972) 464 F.2d 228, 229 (per curiam) [front porch of home]), pose distinguishable facts (Bielicki v. Superior Court (1962) 57 Cal.2d 602, 604 [21 Cal.Rptr. 552, 371 P.2d 288] [observation of public toilet stalls from a hole in the ceiling]) or are silent as to whether the police were standing in a place open to the public (People v. Willard (1965) 238 Cal.App.2d 292, 297 [47 Cal.Rptr. 734] [police entered open gate, stepped on porch to back door and looked through screen door]; People v. Martin (1955) 45 Cal.2d 755, 758 [290 P.2d 855] [police looked through rear window of small office building]).
Thus, while it is certainly true that “ ‘in striking a balance between the rights of the individual and the needs of law enforcement, the Fourth Amendment itself [does not] draw[] the blinds the occupant could have drawn but did not’ ” (Berutko, supra, 71 Cal.2d at p. 93, italics omitted, [834]*834quoting State v. Smith (1962) 37 NJ. 481, 496 [181 A.2d 761]), that pithy statement was made in the context of an observation by police who were standing in a location to which the public was invited, i.e., the front of an apartment building (.Berutko, supra, at p. 88). Accordingly, neither Berutko nor the other cases respondent cites create an “unshuttered window” exception to the Fourth Amendment’s warrant requirement that supersedes Lorenzana's reliance on the fact that police were not entitled to be in the defendant’s side yard.
Nor is it significant, as respondent argues, that Officers Wood and Mora observed defendant for only a short time (perhaps only a minute), whereas the officer in Lorenzana watched and listened for 15 full minutes. It is the nature, not the duration, of the intrusion that controls this case. Had Wood and Mora been standing on a public sidewalk, they could have observed defendant for as long as they wished. Conversely, had the officer in Lorenzana peered through the small opening in the window for only 60 seconds, he would still have conducted an illegal warrantless search because he was standing on private property onto which he had not been invited.
Respondent and the dissent also argue Lorenzana is distinguishable because the officers in that case were directed to the house by a tip of drug dealing, and thus were investigating the very crime they ultimately discovered. By contrast, Officers Wood and Mora were investigating a noise complaint, had not targeted defendant’s house for surveillance, and only by accident—characterized by the dissent in the Court of Appeal as a “luck out arrest”—discovered defendant packaging cocaine.
That police had not targeted defendant’s house for an investigation into drug dealing, and only inadvertently discovered him engaging in that crime, does not change the fact that police acquired the evidence of his crime by watching him through a window from a vantage point to which neither they nor the public had been invited. The relevance of police motive was raised in Ciraolo, supra, 476 U.S. 207, where the defendant suggested the fact police were in a public airspace when they viewed the marijuana plants in his yard was insufficient to compromise his expectation of privacy when “the viewing is motivated by a law enforcement purpose, and not the result of a casual, accidental observation.” (Id. at p. 212 [106 S.Ct. at p. 1812].)
The high court accorded no weight to the police officer’s motive, relying solely on the fact the officer’s vantage point was open to the public. “That the observation from aircraft was directed at identifying the plants and the officers were trained to recognize marijuana is irrelevant. . . . Any member of the public flying in this airspace who glanced down could have seen [835]*835everything that these officers observed. On this record, we readily conclude that respondent’s expectation that his garden was protected from such observation is unreasonable and is not an expectation that society is prepared to honor.” (Ciraolo, supra, 476 U.S. at pp. 213-214 [106 S.Ct. at p. 18l3], fn. omitted.) Similarly, we fail to see why the fact that Officers Wood and Mora entered defendant’s side yard for reasons unrelated to seeking evidence of drug sales should be relevant to determining the reasonableness of defendant’s expectation of privacy.2
Respondent contends that Officers Wood and Mora’s observations were constitutionally permissible because “nothing prohibited access to and from [the] side yard from the street along the side of the house.” We might add that, from the photographs of the scene included in the record, one might expect that at some point, a neighbor’s child, should the need arise, might retrieve an errant ball or loose pet from the side yard of defendant’s home. Similarly, an employee of the local utility company might at some point enter the yard to read the meter, were one located there. Admittedly there was no fence, no sign proclaiming “No trespassing,” no impediment to entry.
Nevertheless, we cannot accept the proposition that defendant forfeited the expectation his property would remain private simply because he did not erect an impregnable barrier to access. Recalling that the lodestar of our inquiry is the reasonableness of defendant’s expectation of privacy, we assume for the sake of argument the meter reader or the child chasing a ball or pet may have implied consent to enter the yard for that narrow reason, for a limited time, and during a reasonable hour. Certainly the same cannot be said for the unconsented-to intrusion by police at 11:00 o’clock at night. (See Pen. Code, § 647, subd. (i) [a person commits misdemeanor of disorderly conduct “[w]ho, while loitering, prowling, or wandering upon the private property of another, at any time, peeks in the door or window of any inhabited building or structure, without visible or lawful business with the owner or occupant”]; see also Bond, supra, 529 U.S. at pp. 337-338 [120 S.Ct. at pp. 1464-1465, 146 L.Ed.2d at p. 370] [placing one’s baggage in the overhead compartment in a bus, where other passengers may touch and move it, does not relinquish the expectation of privacy in the bag’s contents, such that police may feel the bag in an exploratory manner to try and determine its contents].)
[836]*836That is. not to say we find Officers Wood and Mora’s search unlawful merely because they were trespassing on defendant’s private property.3 The Supreme Court’s decision in Katz, supra, 389 U.S. 347, “refused to lock the Fourth Amendment into instances of actual physical trespass.” (United States v. United States District Court, supra, 407 U.S. at p. 313 [92 S.Ct. at p. 2135]; see also Ciraolo, supra, 476 U.S. at p. 223 [106 S.Ct. at p. 1818] (dis. opn. of Powell, J.) [“Since Katz, we have consistently held that the presence or absence of physical trespass by police is constitutionally irrelevant to the question whether society is prepared to recognize an asserted privacy interest as reasonable.”].) For example, Katz, a seminal case in Fourth Amendment jurisprudence, involved wiretapping, an intrusion into privacy not easily amenable to a trespassing analysis. The high court found police invaded that defendant’s reasonable expectation of privacy even though they did not trespass on his property.
Moreover, even without a warrant, police officers may intrude onto private property if the surrounding facts provide cause to believe an emergency situation exists. Thus, had Wood and Mora been dispatched to defendant’s house in response to a report of gunshots being fired, of screams being heard, or of a riot, a stabbing or some other serious crime, we cannot say their entry into the side yard would have been unlawful. Indeed, had the officers on their arrival at defendant’s house heard a raucous party, confirming the anonymous complaint that brought them there in the first place, and had they then banged on the front door to no avail, their entry into the side yard in an attempt to seek the source of the noise would likely have been justified.
The facts here paint quite a different picture: Called to investigate a complaint of excessive noise, an infraction under the city’s municipal ordinances, the officers arrived at defendant’s home late in the evening and heard no such noise. Without bothering to knock on defendant’s front door, they proceeded directly into his darkened side yard. Most persons, we believe, would be surprised, indeed startled, to look out their bedroom window at such an hour to find police officers standing in their yard looking back at them.
In short, we find this case is governed by Lorenzana, supra, 9 Cal.3d 626. Although Lorenzana was decided prior to the enactment of Proposition 8 in [837]*8371982, no post -Lorenzana decision by the United States Supreme Court casts any doubt on its primary reliance on the public or private nature of the police officer’s vantage point as a controlling factor in determining the lawfulness of the officer’s warrantless observations of citizens’ conduct inside the privacy of their homes. (See In re Tyrell /., supra, 8 Cal.4th at p. 79 [Prop. 8 constrains this court to follow Supreme Court decisions; those of lower federal courts are persuasive but not controlling].) Significantly, respondent does not cite any Supreme Court authority requiring we uphold the trial court’s denial of defendant’s suppression motion.
Nor are we persuaded by the lower federal court decisions cited by the dissent in support. First, none is as close to the facts of this case as Lorenzana, supra, 9 Cal.3d 626. Second, of those that indicate the site of the observation, most pose distinguishable facts, in that the observations were made from arguably public areas. (U.S. v. Taylor (4th Cir. 1996) 90 F.3d 903 [front porch]; U.S. v. James (7th Cir. 1994) 40 F.3d 850 [paved walkway along the side of a house]; U.S. v. Evans (7th Cir. 1994) 27 F.3d 1219 [driveway].) In short, none of the cited lower federal court cases convince us to abandon our decision in Lorenzana.
Conclusion
It is not by coincidence that the Fourth Amendment expressly commands that “[t]he right of the people to be secure in their . . . houses . . . shall not be violated.” (U.S. Const., 4th Amend., italics added.) The Framers’ interest that we remain secure from government intrusion in our homes was a paramount concern. When Officers Wood and Mora peered into defendant’s home through his window, they were standing in a place to which neither they nor the public had been invited, and no other circumstances authorized their entry into defendant’s yard. Accordingly, defendant retained a reasonable expectation of privacy over his activities, the officers’ observation of him was a search within the meaning of the Fourth Amendment, and respondent asserts no satisfactory justification for their dispensing with a warrant.4
As noted, if the facts were different, perhaps only slightly so, we might conclude the officers were entitled to enter defendant’s yard, thereby validating the lawfulness of their observations of defendant through his bedroom [838]*838window. The lateness of the hour, the relative lack of seriousness of the phoned-in complaint, and the failure first to knock on defendant’s front door, all are relevant to evaluating the reasonableness of the officers’ conduct in this case. We cannot say, however, that the officers, having arrived at defendant’s house close to midnight in response to an anonymous complaint of a loud party and perceiving nothing amiss, were entitled to enter defendant’s private property without a warrant and look through his windows. To the contrary, we find defendant’s expectation that no one would be in his side yard so late at night was a reasonable one.
Finally, although the line we draw today lets an unquestionably guilty man go free, we observe that “constitutional lines have to be drawn, and on one side of every one of them is an otherwise sympathetic case that provokes impatience with the Constitution and with the line. But constitutional lines are the price of constitutional government.” (Agostini v. Felton (1997) 521 U.S. 203, 254 [117 S.Ct. 1997, 2026, 138 L.Ed.2d 391] (dis. opn. of Souter, J.).)
The decision of the Court of Appeal is affirmed.
Mosk, J., Kennard, J., and Brown, J., concurred.