(dissenting):
The record in this case is crystal clear that a government agent (DiGravio), believing that he already had enough evidence to convict appellant (Nussen), who was then under arrest and indictment for conspiracy to possess and distribute a controlled substance in violation of 21 U.S.C. § 846, asked appellant to furnish information that might lead to the arrest and conviction of his source. When appellant expressed apprehension lest a statement given by him might be used to build a larger case against himself the agent, instead of refusing any assurance or giving Nussen a qualified assurance, granted him blanket immunity from the use against him of any self-incriminating statement that he might make. According to Agent DiGravio’s own testimony, this immunity took the form of assurances to appellant (1) that the agent “was not interested in developing a tighter ease on Mr. Nussen” (Tr. 333); (2) “that what he [Nussen] said would not be used against him” (Tr. 333); (3) “that we weren’t interested in his cooperation to further this case . and that we were not now interested in any of his past conduct” (Tr. 299-*23300); (4) that “[w]e were at this point, moving onto the next potential defendant . that we were not working on him as a defendant, but at this time moving ahead attempting to break the ease to the next higher stage” (Tr. 299-300); and (5) that “We were no longer working on Milton Nussen” (Tr. 321). It was only after receiving these assurances that Nussen furnished the self-incriminatory statements introduced by the government on rebuttal at trial.
It is elementary that the effect of a blanket immunity is to preclude the government from using against a defendant any resulting statements obtained from him. See Bram v. United States, 168 U.S. 532, 542-43, 18 S.Ct. 183, 42 L.Ed. 568 (1897). The fact that he had been given warnings as prescribed by Miranda v. Arizona, 384 U.S. 436, 86 S.Ct. 1602, 16 L.Ed.2d 694 (1966), does not render his statement admissible against him in the absence of any showing that he “knowingly and intelligently” waived his right against self-incrimination before making the statement, see 384 U.S. at 479, 86 S.Ct. 1602.1 In Shotwell Mfg. Co. v. United States, 371 U.S. 341, 83 S.Ct. 448, 9 L.Ed.2d 357 (1963), Justice Harlan, speaking with respect to the admissibility of “evidence of guilt induced from a person under a governmental promise of immunity,” stated the Court’s view that “such evidence must be excluded under the Self-Incrimination Clause of the Fifth Amendment. . . Evidence so procured can no more be regarded as the product of a free act of the accused than that obtained by official physical or psychological coercion.” 371 U.S. at 347-48, 83 S.Ct. at 453.2
The majority seeks to circumvent application of the foregoing basic principle by holding that the immunity given by agent DiGravio to appellant was limited to other cases that might be developed through use of appellant’s statement and did not extend to the existing case against him. The difficulty with this position is that, despite extended examination of Agent DiGravio on the subject, both at the suppression hearing and at trial, in the course of which the idea of a limited immunity was suggested, he was never willing to state unequivocally that he had limited the promises given by him to Nussen. Although the record reveals that Nussen was initially concerned about the possibility that his statement might be used to develop “a more encompassing case” against him, it is equally clear that the agent, apparently in the belief that he had already developed a solid case against Nussen and in the desire to ease any fears that Nussen might have regarding the consequences of his cooperation, promised blanket rather than limited immunity. In this way, of course, the agent avoided the risk of losing the opportunity to obtain evidence that might incriminate the “higher-ups.”
In concluding that DiGravio’s promises of immunity did not extend to this case, the majority relies heavily on the following excerpt from Agent DiGravio’s testimony:
“At this time Mr. Nussen questioned the fact of whether what he said at this time would be used against him to further *24develop a more encompassing case involving any drug dealings, and other transactions he had engaged in prior to or subsequent to July 16,1974. Mr. Nussen and I shook hands at this time. I informed him that what he said would not be used against him. That we were at this time attempting to further the case in order to reach the source of supply of the 11,000 stimulant tablets. That I was not interested in developing a tighter case on Mr. Nussen.” ' (Tr. 333) (Emphasis added).
This testimony hardly offers clear support for the majority’s interpretation of Agent DiGravio’s statement. Although appellant’s expression of concern that a statement given by him would be used to develop a “more encompassing case” against him might be interpreted, though not necessarily, as referring only to other transactions, the agent’s sweeping assurances went much further, indicating an attempt to ease any fears appellant might have that his cooperation with the government could get him into any further trouble. Furthermore this testimony of Agent DiGravio was not made at the suppression hearing at which Judge Platt denied appellant’s motion to exclude any testimony about these statements, but in the course of Agent DiGravio’s later testimony in open court, after repeated but unsuccessful efforts had been made to elicit from the witness a limitation upon the assurances that had been given by him to Nussen.
An examination of the testimony actually given by Agent DiGravio at the suppression hearing indicates even more clearly that he made an absolute offer of immunity which would extend to the present prosecution. When first asked by the prosecution at the suppression hearing to describe his conversation with appellant, DiGravio replied as follows:
“Q. Will you please tell us the circumstances and how these statements arose?
A. During the processing of Milton Nussen as I stated the other day, he made certain admissions which I mentioned. Then, there came a time during the processing after he had already stated that he wanted to cooperate with the United States Government, he became a little hesitant as most defendants do wanting to know that we weren’t going to build a larger case on him and whether what he was going to say would put him in more jeopardy than he was already in.
I assured him that we weren’t interested in his cooperation to further this case and to get to the source of the 11,000 stimulant tables [sic] and that we were not now interested in any of his past conduct. We were at this point, moving on to the next potential defendant. At that time, I shook hands with Milton Nus-sen in a gesture that we were not working on him as a defendant, but at this time moving ahead, attempting to break the case to the next higher stage.” (Tr. 299-300) (Emphasis added).
This initial account by Agent DiGravio of the conversation with appellant cannot support the conclusion that he carefully limited his assurances of immunity as the government now claims he did. Rather, it is clear that the agent and the suspect had reached an understanding that the prosecution in the present case would be carried on with the evidence already in hand, and that Nus-sen could talk without any apprehension that his statements would put him in greater jeopardy in this or any other case. After further suppression hearing testimony on direct examination about the nature of the help which appellant might give the government, cross-examination ensued, during which DiGravio specifically testified that he told Nussen that nothing he said would be used against him. The phrase piqued the curiosity of the trial judge, who then himself questioned Agent DiGravio, seeking to determine whether the promise of immunity was limited as the government claimed:
“The Court: . . . When you said, as I believe you said on cross-examination at one point that the statements that he made, the further statements that he made were not going to be used against him. Was that made in the context ‘not going to be used against him’ in this case *25or ‘not going to be used against him’ in building a larger case as you heretofore indicated?
“The Witness: I meant it that what he said in—
“The Court: Not what you meant in, what context as the statement.
“The Witness: The context was made that what he said would not be used against him to develop an entire case or a larger case. It would not be used to drag in other narcotic transactions or other types of incidents that had occurred.
“What we needed from him was assurance that he in fact could help us to further this case to get to the source of supply.” (Tr. 319-20) (Emphasis added).
It is difficult to imagine how the trial judge could have posed a question which more clearly raised the issue now before us. Yet Agent DiGravio’s response once again indicates that his offer of immunity was not limited, but rather extended to the use made of the testimony in the present case.
Under further cross-examination, Agent DiGravio expanded upon his answer to Judge Platt’s question, and again indicated that he gave broad assurances of immunity to appellant. Moreover, his testimony to this effect does not seem to have been wrung from him by insistent or confusing questioning by defense counsel, but rather was freely offered:
“Q. You just told Judge Platt what you claimed the context of the statement was. That it would not be used to tighten the existing case against this defendant; is that correct?
“A. I also stated more than that. I said to enlarge, to entrap the individual, where he felt as though we were still working on him. We were no longer working on Milton Nussen.” (Tr. 321).
Taken as a whole, the record does not support a finding that Agent DiGravio assured appellant only that his statements would not be used in prosecutions for other criminal offenses. On the contrary, it clearly indicates that DiGravio made a blanket promise of immunity to appellant which induced his subsequent statements. Even if there were ambiguity as to the meaning, it should be resolved in appellant’s favor. Thus the use of Nussen’s statements at trial violated his Fifth Amendment privilege against self-incrimination. See Miranda v. Arizona, supra, 384 U.S. at 469, 86 S.Ct. 1602; Shotwell Mfg. Co. v. United States, supra, 371 U.S. at 347-48, 83 S.Ct. 448.
The government also contends that, while the use of these statements on its direct case might have violated appellant’s Fifth Amendment privilege, the prosecution’s use of them to rebut defendant’s alibi witness is nonetheless permissible, by analogy to Harris v. New York, 401 U.S. 222, 91 S.Ct. 643, 28 L.Ed.2d 1 (1971). See also Oregon v. Hass, 420 U.S. 714, 95 S.Ct. 1215, 43 L.Ed.2d 570 (1975). The reasoning advanced in support of this position is that if such statements can be used under Harris and Hass to impeach a testifying defendant, they should be similarly available to counter possible perjury by an alibi witness testifying for the defense. I concur in the majority’s rejection of this attempt to create a new exception to the requirements of Miranda. First of all, the statements in question were admitted for substantive use in determining the appellant’s guilt, not merely for the limited purpose of impeaching credibility, which is the only purpose permitted by Harris, see 401 U.S. at 225-26, 91 S.Ct. 643, and Hass, see 420 U.S. at 722, 95 S.Ct. 1215. Secondly, the Harris-Hass doctrine requires that such statements may be so used only if they would have been admissible under preMiranda standards. See 420 U.S. at 723, 95 S.Ct. 1215. The statements made by appellant in response to a promise of immunity would not have been admissible even prior to Miranda. See Shotwell Mfg. Co. v. United States, supra; cf. Bram v. United States, 168 U.S. 532, 542-43, 18 S.Ct. 183, 42 L.Ed. 568 (1897). See also Maguire, Evidence of Guilt 139 (1959); Developments in the Law — Confessions, 79 Harv.L.Rev. 935, 954-61 (1966).
Moreover, the Harris and Hass decisions only allow such uses of statements taken in violation of Miranda as will not provide any significant incentives for police officers to *26violate the Miranda guidelines. See Oregon v. Hass, supra, 420 U.S. at 723, 95 S.Ct. 1215; Harris v. New York, supra, 401 U.S. at 225, 91 S.Ct. 643. The view of the Harris court that allowing such statements to be used to impeach a testifying defendant does not provide such incentives to ignore Miranda has itself been criticized by some commentators, see Dershowitz and Ely, Harris v. New York: Some Anxious Observations on the Candor and Logic of the Emerging Nixon Majority, 80 Yale L.J. 1198, 1218-21 (1971), and if such statements were also useable as the government here suggests, insignificant incentives to disregard Miranda would almost certainly arise. Police officers would be tempted to violate Miranda guidelines in order to obtain incriminating statements from a suspect which could then be used as a lever not only to keep him from testifying on his own behalf, see id., but also to prevent him from offering any defense at all since, if he offered such a defense, the incriminating statements could then be used in rebuttal. In short, the “exception” to Miranda which the government here advocates would swallow the rule.
Finally, I must dissent from the majority view that the error concerning the admission of appellant’s statements were harmless. Nussen, it should be remembered, was convicted only on the conspiracy count; the extent of his participation in the transaction thus was a crucial issue for the jury’s consideration. Aside from the admissions erroneously admitted, all of the testimony implicating Nussen as the man who arranged to provide the pills came from Rudich, an alleged co-conspirator, and a witness whose credibility was open to serious question because of the benefits he hoped to obtain from cooperation with the government, his criminal record, and his use of drugs. None of the admissions by Nussen properly introduced on the government’s direct case corroborated Rudich’s story about Nussen’s central role in the transaction; they indicated merely that Nussen had been on the scene that night, had panicked and falsely reported his car stolen.
By contrast, Nussen’s later, erroneously introduced admission that the pills were supplied by one Jerry Abrams, who worked at the Concord Hotel in upstate New York, directly corroborated Rudich’s story that Nussen was a member of the conspiracy, indeed a key link in the chain of distribution of the pills. Moreover, the erroneously introduced admission by Nussen that he planned to procure a false alibi witness went far toward undercutting the testimony of the alibi witness he did introduce who, if believed, would have exculpated him from any direct part in the parking lot transaction. Indeed, the fact that the government felt it desirable to introduce these later admissions may imply that it had some qualms about the strength of its case at that point. Thus, in view of the fact that the erroneously introduced admissions both materially strengthened the government’s evidence on whether Nussen was a member of the conspiracy, and undercut Nussen’s alibi I am not satisfied beyond a reasonable doubt, as Chapman v. California, 386 U.S. 18, 87 S.Ct. 824, 17 L.Ed.2d 705 (1967), requires, that the error was harmless.
. Agent DiGravio testified that he did not offer any written waiver form for defendant to sign, even though the Drug Enforcement Administration does have such forms for use by agents, if they so desire. Agent DiGravio stated that it was his practice never to use such a written waiver. I do not rely on the absence of a written agreement concerning the extent of immunity, since a Miranda waiver need not be written, see United States v. Cassino, 467 F.2d 610, 620 n. 30 (2d Cir. 1972), cert. denied, 410 U.S. 928, 93 S.Ct. 1363, 35 L.Ed.2d 590 (1973), but prudence might well dictate that when police officers make such complicated agreements of partial immunity as the government argues was intended in this case, the agreements be reduced to writing to avoid any subsequent complications.
. Our decisions in United States v. Pomares, 499 F.2d 1220 (2d Cir.), cert. denied, 419 U.S. 1032, 95 S.Ct. 514, 42 L.Ed.2d 307 (1974), and United States v. Ferrara, 377 F.2d 16 (2d Cir.), cert. denied, 489 U.S. 908, 88 S.Ct. 225, 19 L.Ed.2d 225 (1967), do not cast any doubt on this rule. Both cases involve only promises to, or expectations by, a defendant that cooperation with the police might provide some benefits, such as the possibility of release on bail. There was no hint in either case that the police offered use immunity to the suspect.