dissenting:
The probable cause supporting the war-rantless entry, arrest, search and seizure of evidence in this case was gained when police officers knowingly trespassed on a private lawn in order to peer through a basement window.1 The panel opinion in which I joined concluded that this search was unlawful. I continue to believe this conclusion is accurate and that the subsequent intrusions were thereby rendered unlawful. See United States v. Ralph Johnson, No. 73-2221 June 16, 1975, slip at 714-16. Although the panel opinion did not rest solely on this issue because it had not been briefed on appeal, upon further reflection I feel that the illegality of the initial window observation provides a sufficient as well as the sturdiest basis for invalidating the police action.
I. APPLICABILITY OF THE PLAIN ERROR RULE
The majority asserts that the window search issue is appealable only under the *854plain error rule because the appellant himself did not raise the issue at the suppression hearing.2 Rule 52(b) Fed.R.Crim.P. states, “Plain errors or defects affecting substantial rights may be noticed although they were not brought to the attention of the court.” This rule is primarily grounded in considerations of fairness to the opposing party and preservation of the integrity of the trial court. United States v. Atkinson, 297 U.S. 157, 159, 56 S.Ct. 391, 80 L.Ed. 555 (1936). Having carefully examined the transcript of the suppression hearing, I am convinced that the unlawfulness of the window search was “brought to the attention of the court” with sufficient clarity to take this case out of the plain error rule.3 Nor should the plain error rule be invoked because appellant did not raise the issue of the window search in his argument before the panel; the panel properly determined the legality of the window search and the government has had ample opportunity to defend that search on rehearing. In any event, even if I am mistaken in either of these two conclusions, invoking the plain error rule should not affect the outcome of this case because the error here clearly affected substantial rights.
Appellant was tried jointly with five other defendants accused of the same crime. Although at the trial the court recognized the divergence of the defendants’ interests, (T.T. pp. 25, 26), at the suppression hearing the trial judge naturally and correctly assumed the interests of the individual defendants were the same.4 Before allowing any witnesses to be heard, he said to the six defense counsel:
Very well. Now which counsel will serve as spokesman for the defense counsel to make a statement, preliminary statement, as to what the position of the defense is? (M.T. Nov. 1, p. 7).
The trial judge later allowed the other counsel to supplement lead counsel’s remarks, as well as to cross-examine the government witnesses, but his question clearly shows he was prepared to treat issues raised by one defendant at the suppression hearing as being raised by all.
Later statements by the trial judge confirm this view. For example, counsel for defendant Riggins, the third counsel to cross-examine Officer Simms, asked Simms if he knew he was on private property when he looked through the basement window. Simms replied, “Yes, sir, I stated previously I knew it was private property.” At this point, the trial judge broke in and said, “Counsel, now don’t make your questions so repetitious. * * * * I think it is well established it was private property.” (M.T. Nov. 1, pp. 99-100). After hearing this rebuke, it would have been absurd for appellant’s counsel to reestablish points previously made when his turn for cross-examination or argument arose.
With the suppression hearing conducted in this posture, the issue in determining the applicability of the plain error rule is not whether appellant’s counsel personally raised the issue of the window search. Rather, it is whether the issue was raised by the defense team with sufficient clarity to put the government and the trial court on notice that the issue had been raised. The record quite clearly indicates that both were.
As noted above, the various defense counsel elicited testimony from Officer Simms at more than one point to the effect that he knew he was trespassing when he looked *855through the window. (M.T. Nov. 1, at 93, 99, 100). Moreover, at oral argument on the motion to suppress, one defense lawyer squarely challenged the window search, arguing:
Your honor, in reviewing the testimony I would point out that first of all the police had an anonymous call. That in itself would not be sufficient to enter' the premises.
Secondly, Officer Simms stepped upon the private property of individuals in order to look through the window to see the activities that then gave some corroboration to the anonymous call.
We maintain this stepping on private property just the anonymous call in and of itself was iiiegal (M.T. Nov. 9, p. 46) (emphasis added).
Furthermore, the government counsel at oral argument countered this argument at some length concluding that the initial intrusion, “if in fact it was one was a lawful one or a reasonable one in taking into consideration all the circumstances.” (M.T. Nov. 9, pp. 55-6).
T-he majority is concededly correct in observing that the unlawfulness of the window search was not the primary argument for suppression. However, the issue was clearly brought to the attention of the trial judge and the government through testimony and argument, and that is all Rule 52(b) requires.5 It seems plain therefore that the plain error rule is not applicable on appeal on the grounds appellant did not challenge window search at the suppression hearing.
Nor can it reasonably be suggested that the en banc court should not review this case under ordinary principles of review; the policies underlying the plain error rule do not require its application. The challenge to the window search has been expressly brought to the attention of the trial court and this court en banc, so neither the government nor the court system has been prejudiced in any way by the failure of appellant to address the issue before the panel. The Government has in fact defended the window search at the suppression hearing and in its brief and argument before the en banc court.
Furthermore, even if I am mistaken and the plain error rule should be applied in this case, the panel acted properly in determining the legality of the window search. An appellate court can notice sua sponte a plain error affecting substantial rights not brought to its, as opposed to the trial court’s, attention. Silber v. United States, 370 U.S. 717, 82 S.Ct. 1287, 8 L.Ed.2d 798 (1962); United States v. Atkinson, supra, and Tatum v. United States, 88 U.S.App. D.C. 386, 190 F.2d 612 (1951). Here there can be little question that the unlawful window search “affected substantial rights” within the meaning of Rule 52(b).6 Al*856though the trespass was relatively minor in terms of distance, the information gathered thereby supplies the justification for all of the subsequent intrusions.7
II. THE UNLAWFULNESS OF THE WINDOW SEARCH
Warrantless arrests and searches are, with only a few narrowly defined exceptions unreasonable per se, e. g. Katz v. United States, 389 U.S. 347, 357, 88 S.Ct. 507, 19 L.Ed.2d 576 (1971), and the government bears the burden of demonstrating the applicability of an exception, Coolidge v. New Hampshire, 403 U.S. 443, 455, 91 S.Ct. 2022, 29 L.Ed.2d 564 (1971). In this case, the only exception arguably applicable is the “plain view” doctrine as expressed in Harris v. United States, 390 U.S. 234, 88 S.Ct. 992, 19 L.Ed. 1067 (1968). In Harris, the Court wrote that “objects falling in the plain view of an officer who has a right to be in the position to have that view are subject to seizure and may be introduced in evidence.” Harris, supra, 390 U.S. 236, 88 S.Ct. 992, 19 L.Ed. 1067. (emphasis added).
Although the majority never expressly states that it is affirming the window search under the plain view doctrine, this is evidently what it has in mind when, quoting language from Seventh Circuit plain view cases,8 it concludes that a mere “technical trespass” “did not transform an otherwise reasonable investigation into an unreasonable search.” (Majority opinion p. -- of 182 U.S.App.D.C., p. 841 of 561 F.2d) Conceptually, an officer has not conducted a search when he merely observes something that is in plain view. United States v. Hanrahan, 442 F.2d at 663; Ponce v. Craven, 409 F.2d 621 (9th Cir. 1969). However, as Harris makes clear, the plain view exception operates only when the officer is positioned in a place where he has a right to be. If the rule were otherwise, the police could eviscerate the warrant requirement by maneuvering themselves into positions where the object being sought was plainly within view, regardless of its location. The thrust of the majority’s argument must be that, for the purposes of Harris, an officer is not to be considered as being in a place where he has no right to be when his trespass onto private property is minimal.9
*857I have several difficulties with this argument. First, the trespass cannot be dismissed out of hand because it was minimal in terms of distance.10 In both Hanahan and Conner the Seventh Circuit was able to label the inadvertent police trespasses as “technical” and therefore irrelevant because they did not enhance the ability of the police to view the objects observed. In each case, the court specifically found that, whether or not the observing officer’s foot happened to alight on the thin strip of grass separating the garage window through which the observation was made and the public sidewalk on which they were standing, the officers could and did view the interior of the garages from the public sidewalk. United States v. Hanahan, 442 F.2d 649, 654 (7 Cir. 1971), United States v. Conner, 478 F.2d 1320, 1323 (7 Cir. 1973). Here, to the contrary, the government has not satisfied its burden of demonstrating that the officer’s trespass was technical in the sense of being similarly immaterial. Thus, I cannot disregard the trespass in order to conclude that Officer Simms was in a place where he had a right to be when he peered through the window.
Second, the Supreme Court has repeatedly stressed that the exceptions to the warrant requirement are narrow in scope. Coolidge v. New Hampshire, 403 U.S. 443, 445, 91 S.Ct. 2022, 29 L.Ed.2d 564 (1970), United States v. Jeffers, 342 U.S. 48, 51, 72 S.Ct. 93, 96 L.Ed. 59 (1951). Here, even though the legality of the window search was challenged at the suppression hearing the government never demonstrated that it fell within one of the recognized exceptions to the warrant requirement. To the contrary, Officer Simms’s testimony strongly suggests that the plain view doctrine cannot justify the window search. Simms admitted he knowingly trespassed to accomplish the search, that he knew he was not, to use the words of Harris, in a place where he had a right to be.
Furthermore, I agree with Judge Leven-thal’s observation that focussing on whether a trespass is minimal in terms of distance is not responsive to the broad question of the Fourth Amendment, which is, as he correctly observes, whether the trespasser “was encroaching on a reasonable expectation of privacy that comes within the fair *858intendment of the Fourth Amendment.” (Leventhal concurring p. - of 182 U.S. App.D.C., p. 845 of 561 F.2d). However, I disagree with his conclusion that we should not determine the legality of the window search because the record does not adequately disclose whether the officers invaded reasonable expectations of privacy.11 In my view, the sparseness of the record on this point is attributable to the government’s failure to demonstrate the applicability of the “plain view” doctrine. Most of us, I would submit, would expect that our actions are private when they can only be observed by trespassing prowlers. This would be especially true in the middle of the night.12 I believe most people would be so disturbed at the sight of a face peering through their basement window in the middle of the night that they would call the police; after today’s decision, the police may already be there.
Ironically, this case turns the development of the Fourth Amendment straight on its head. At one time it was thought that the Fourth Amendment only forbade physical trespasses, e. g. Olmstead v. United States, 277 U.S. 438, 48 S.Ct. 564, 72 L.Ed. 944. More recently, the Supreme Court has come to view the protection of the Fourth Amendment more expansively, holding that people and not places come within its ambit. Katz v. United States, 389 U.S. 347, 88 S.Ct. 507, 19 L.Ed.2d 576 (1967). Although the law of trespass formed the bedrock on which these subsequent expansions rest, the majority today in effect states that a person does not always have a reasonable expectation that he will not be spied upon by a trespassing police officer, thereby converting an expansion of the Fourth Amendment into a contradiction. Contrary to the majority, I think it is reasonable for a person to expect his activities to be safe from the eye of a person who must trespass to view him.13 In light of the narrowness of the warrant exceptions, I doubt the government would ever be able to justify a search on plain view grounds when it was necessary for the officer to trespass in order to achieve the view.
CONCLUSION
In certain respects this case is not an appealing one in which to dissent, there being little doubt that the appellant committed the offense charged. Nevertheless, a search is not to be upheld because of what it discloses. I understand my brethren’s reluctance to let the offender escape the law because “the constable blundered.” When the Supreme Court created the exclusionary rule it did so reluctantly. It had no authority to discipline the law enforcement *859authorities; so to keep the Fourth Amend-, ment from becoming a dead letter because of law enforcement lawlessness its hard choice was to adopt the rule. The rule exacts a high price which can be avoided if either the executive or legislative branches were to put teeth into the Fourth Amendment. Although the courts have long sought help in protecting the Fourth Amendment, neither the legislative or executive branches have taken effective steps to discipline or penalize the offending law officers. Absent such steps, the courts must forthrightly choose either to abandon the Fourth Amendment or refuse to place their imprimatur on its violation.
. Probable cause did not exist until the police had peered through the basement window. An anonymous tip by itself cannot constitute probable cause. Aguilar v. Texas, 378 U.S. 108, 84 S.Ct. 1509, 12 L.Ed.2d 723 (1964). Nor was the tip sufficiently corroborated when the officers initially saw the light emanating from the basement window to satisfy Draper v. United States, 358 U.S. 307, 79 S.Ct. 329, 3 L.Ed.2d 327 (1958). As in Spinelli v. United States, 393 U.S. 410, 419, 89 S.Ct. 584, 21 L.Ed.2d 637 (1969), the police here independently corroborated only one small detail of the anonymous tip whereas in Draper the police independently corroborated a detailed tip in all but one unimportant respect.
Judge MacKinnon, does not contend, as indeed he could not under Aguilar, that the anonymous tip gave the officers probable cause to search. In fact, he twice appears to concede that probable cause did not exist. (Concurring draft at-,-of 182 U.S.App.D.C., at--, 849-853 of 561 F.2d). Nevertheless, he argues that the anonymous tip created exigent circumstances that justified the search. However, the existence of exigent circumstances merely permits the searching officer to by-pass the warrant requirement. Warden v. Hayden, 387 U.S. 294, 298, 299, 87 S.Ct. 1642, 18 L.Ed.2d 782 (1966). Exigent circumstances have never been thought to substitute for probable cause. Compare, Dorman v. United States, 140 U.S. App.D.C. 313, 321-323, 435 F.2d 385, 393-95 (1970) (en banc) (probable cause must be clearly shown to justify warrantless search, especially at night).
Nor can the window search be justified by analogy to Terry v. Ohio, 392 U.S. 1, 88 S.Ct. 1868, 20 L.Ed.2d 889 (1968). See note 9 infra. Terry does not, as Judge MacKinnon’s opinion implies, read probable cause out of the Fourth Amendment by making “reasonableness” the sole test of constitutionality. In creating an exception to the probable cause requirement, the Terry Court clearly reaffirmed the principle that probable cause was generally required, 392 U.S. at 20, 88 S.Ct. 1868. Under Terry reasonableness is the exclusive test of constitutionality only when, as is the case with brief, on-the-street encounters, the police conduct in question “historically has not been, and as a practical matter could not be, subjected to the ' warrant procedure.” 392 U.S. at 20, 88 S.Ct. at 1879. It could not seriously be maintained that searches of a home for evidence of criminality fall into this category. And even if resort to the warrant procedure would have been impractical in this case, Terry also reaffirms that such exigent circumstances only eliminate the need for the warrant, not the need for probable cause. Id.
. The majority never makes clear how it feels the plain error rule changes the result in this case.
. Judge Leventhal in his separate concurrence recognizes that the issue of the window search was brought to the attention of the trial court. He concludes, however, that the record is not sufficiently developed to permit appellate review on this issue. If this were correct, which I doubt, see note 10 infra, I see no reason for penalizing appellant by refusing review altogether. Since the legality of the window search has been properly raised, the very least required by fundamental fairness is to remand this case to the trial court to take further evidence on any inadequately developed factual issues.
. This is so even though the defendants had not all joined in one motion to suppress. (M.T. Nov. 1, p. 7.)
. The fact that the window search was clearly though not strenuously challenged before the trial court sets this case apart from other cases where this court has invoked the plain error rule. In United States v. White, 139 U.S.App. D.C. 32, 429 F.2d 711 (1970), the court refused to find plain error in the admissibn of evidence where the appellant neither filed a motion to suppress the evidence nor objected to its admission at trial. United States v. Smith, 160 U.S.App.D.C. 221, 490 F.2d 789 (1974), is similar. There the appellant did not object at all to the admission of certain damaging evidence until the case was on appeal. Id., at 226-227, 490 F.2d at 794-5. See also United States v. Diggs, 173 U.S.App.D.C. 95, 522 F.2d 1310 (1975), and United States v. Johnson et al., 539 F.2d 181 (1976).
Finally, a recent Supreme Court case offers considerable guidance on the question of whether the window search is properly before us. In Anderson v. United States, 417 U.S. 211, 94 S.Ct. 2253, 41 L.Ed.2d 20 (1973), the petitioners unsuccessfully sought to advance on appeal a ground for the objection of evidence they had not argued to the trial court. The Supreme Court held that the objection should have been heard, stating:
In view of the fact that petitioners did challenge the admissibility of the . . . testimony at trial, we think it was proper for the Court of Appeals to consider ail grounds related to that underlying objection.
Id. at 211 n.5, 94 S.Ct. at 2259 n.5. In this case, appellant is not seeking to advance a new argument on appeal, but rather to give more emphasis to an argument previously made.
. There are cases which suggest that reversal on a plain error rationale requires more than a simple finding that the error was not harmless. E. g. United States v. Leonard, 161 U.S.App. D.C. 36, 41-42, 494 F.2d 955, 960-61 (1974); United States v. Grasso, 437 F.2d 317, 319 (3d *856Cir.), cert. denied, 403 U.S. 920, 91 S.Ct. 2236, 29 L.Ed. 698 (1971). Fed.R.Crim.P. 52(b), however, makes plain errors and trial defects cognizable if they affect “substantial rights,” the precise standard under which Fed.R.Crim.P. 52(a) requires courts to determine whether an error is harmless. And there are numerous cases where courts have reversed on plain error without finding a “manifest miscarriage of justice” or similarly grave abuse. E. g., United States v. McClain, 142 U.S.App.D.C. 213, 218, 440 F.2d 241, 246 (1971); King v. United States, 125 U.S.App.D.C. 318, 372 F.2d 383 (1967). In any event, I think the harm to appellant is sufficient to meet a threshold higher than simple prejudice, if one is appropriate, particularly in light of the presumption that serious doubts should be resolved in defendant’s favor established by Kotteakos v. United States, 328 U.S. 750, 764, 66 S.Ct. 1239, 90 L.Ed. 1557 (1946).
. Since the plain error rule presupposes the existence of error, but the majority appears to conclude that the window search was lawful, Majority opinion, p. - of 182 U.S.App.D.C., p. 841 of 561 F.2d, and since the majority never suggests that an error was committed that was not “plain” or did not “affect substantial rights,” there seems to be no logical necessity for dragging plain error into this case. One must wonder why the majority has done so for a purpose other than rhetorical. By relying on the plain error rule, the majority is able to avoid expressly deciding that the window search was lawful while leaving the strong suggestion that it was. The majority simply concludes “we do not think that Officer Simms’s testimony exposed plain error affecting substantial rights requiring us to reverse this conviction,” a statement of law which, I submit, has no analytic meaning beyond the bare result.
. United States v. Conner, 478 F.2d 1320, 1323 (7 Cir. 1972); United States v. Hanahan, 442 F.2d 649 (7 Cir. 1971).
. The majority’s discussion of the Hanahan case on p. - of 182 U.S.App.D.C., p. 841 of 561 F.2d (1968), lends credence to this summary of its argument. It is possible, however, to read the majority as justifying the search on the basis of an analogy to Terry v. Ohio, 392 U.S. 1, 88 S.Ct. 1868, 20 L.Ed.2d 889 (1968), in accordance with a suggestion found in the Government’s supplemental brief. P. 9, f. 11. The argument would be that the window search was reasonable because it was the least intrusive means by which the police could corroborate the veracity of the anonymous tip. I *857do not read the majority as making this argument. The majority devotes the bulk of its opinion to a discussion of the substantiality of the trespass. If they were making a least intrusive means argument, the substantiality of the trespass would be irrelevant so long as it was the least substantial trespass necessary to accomplish the search. Furthermore, 1 do not, unlike Judge Leventhal, believe fuller factual development is necessary to appraise whether this trespass can be justified along these lines. If, for example, a warrantless search without probable cause accomplished by a substantial trespass could be justified as the least intrusive means of corroborating a tip, then it is hard to imagine what would be protected under the Fourth Amendment. This contention is, in other words, the type of slippery slope argument that should be rejected out of hand.
. In point of fact, the intrusion was more significant than the majority indicates. First, the majority states the court found the trespass “not to be more than two or three feet.” (Draft p. - of 182 U.S.App.D.C., p. 842 of 561 F.2d.) The court never made such a finding: the trial judge merely observed that the Government counsel was standing two or three feet from a certain object while he was attempting to demonstrate the geography of the relevant house. M.T. Nov. 1, p. 105. Contrary to the majority’s assertion, Officer Simms testified that he “stepped over about five steps or five feet” to reach the window. M.T. Nov. 1, p. 22.
Second, in the circumstances of this case, it defies reality to measure the trespass from the front porch rather than from the sidewalk running parallel to the street. Although it apparently had been assumed throughout the course of litigation that the officers could have walked to the front door to ask questions, they did not do so nor does the record suggest any intent on their part to do so. In fact, the Government supplemental brief contends that it is “ludicrous” to suggest that they should have done so. Govt.Supp.Br. p. 10. A fair reading of the record suggests that if the officers were insistent on corroborating the anonymous tip, the only way they could have done so was by trespassing. This case therefore differs from Conner and Hanahan where the officers trespassed inadvertently and imperceptibly. See Coolidge v. New Hampshire, 403 U.S. 443, 470, 91 S.Ct. 2022, 29 L.Ed.2d 564 (1970). The fact that the officers here could walk to the window on cobblestone rather than on tulips is immaterial in measuring the substantiality of their intentional intrusion.
. Nor would it be appropriate as Judge Leven-thal suggests, p. - of 182 U.S.App.D.C., p. 845 of 561 F.2d, n.l, to avoid decision on the window search because of the inadequacy of the record regarding a possible analogy to Terry v. Ohio, 392 U.S. 1, 88 S.Ct. 1868, 20 L.Ed.2d 889 (1968). As I noted in n.9, supra, I neither read the majority as making such an argument, nor find such an argument persuasive in theory.
. In a similar case several years ago, Judge Wright found it equally difficult to take seriously a government claim that officers had merely observed damaging evidence was in plain view. His words are instructive:
Certainly no one bent on crime is knowingly going to expose to the public the evidence to convict. Here the evidence was locked in a garage, so any suggestion that appellant knowingly exposed it to the public (or the police) would be absurd.
United States v. Wright, 146 U.S.App.D.C. 126, 136, 449 F.2d 1355, 1365 (1971) (dissenting opinion). For better or for worse, the Fourth Amendment protects the guilty as well as the innocent. I find these words applicable in this case as well.
. United States v. Santana, 427 U.S. 38, 96 S.Ct. 2406, 49 L.Ed.2d 300, does not sanction such a contraction. In Santana the Court held that a woman who was standing in a doorway visible to the street was in a “public place” and therefore susceptible to warrantless arrest upon probable cause. Quoting Katz, 389 U.S. at 351, 88 S.Ct. 507 and citing Hester v. United States, 265 U.S. 57, 44 S.Ct. 445, 68 L.Ed. 898 (1924), the Court noted that it was immaterial that the police initially spotted the woman when she was on private property because she had “knowingly” exposed herself to the public. As the citation of Hester, in which open fields were held to be unprotected by the Fourth Amendment, even when privately owned, makes clear, Santana in no way cuts back on Katz.