Appellant is one of 102 narcotics offenders against whom one Metropolitan Police Department undercover agent, Officer Rufus Moore, filed complaints in March 1963. During a period of about seven months beginning in August 1962, Officer Moore operated undercover for the Narcotics Squad and on October 10 and 11, 1962, he observed the transactions which led to the charges against appellant.1 On December 18, 1962, appellant was arrested on an unrelated charge of narcotic vagrancy (of which he was later acquitted) and, on January 18, 1963, he was committed to the District of Columbia Jail upon execution of a warrant charging him with violation of his parole from incarceration for a 1958 narcotics conviction. Thus, appellant was in jail serving the remainder of his 1958 sentence when the warrant based on Officer Moore’s complaint was served upon him.
At the outset, appellant complains that even though the police case against him was complete in October 1962 he was not arrested on those charges until March 1963, and he alleges that this five-month delay was purposeful, deliberate, vexatious, arbitrary and oppressive, and that he was prejudiced thereby. The alleged prejudice, says appellant, lies in his inability to recall the events of October 10 and 11,1962, and to obtain witnesses who could lucidly support his sole affirmative defense of alibi.2 Counsel for appellant, in his brief, invokes the Sixth Amendment right to a speedy trial and Rule 48(b) of the Federal Rules of Criminal Procedure. We think, however, and counsel conceded during oral argument, that neither the Sixth Amendment nor Rule 48(b) is involved here because the time period of the delay was between offense and arrest. See Nickens v. United States, 116 U.S.App.D.C. 338, 339-340, 323 F.2d 808, 809-810 (1963); and Redfield v. United States, 117 U.S.App.D.C. 231, 328 F.2d 532, cert. denied 377 U.S. 972, 84 S.Ct. 1654,12 L.Ed.2d 741 (1964). Rather, the gravamen of appellant’s complaint is that he was denied a fair trial under the due process clause of the Fifth Amendment because of the delay.3
Since the period with which we are concerned, that between commission of an offense and the arrest therefor, is to some extent covered by a statute of limitations,4 one might think that Congress had legislatively determined the question now raised.5 However, the issue here is not about the outer limits of a time period in which a prosecution may be initiated but about the problem of to what extent and under what circum*708stances the police may delay making an arrest once they have sufficient knowledge of a crime to support the arrest of a given individual for that crime.
We think that an accused must show two things in order to invoke an exercise of our supervisory power because of alleged basic “unfairness,” cf. Ross v. United States, infra note 6, resulting from claimed delay in his arrest: that there was no legitimate reason for the delay, and that he was prejudiced by the delay. Appellant bears the burden of establishing his claim, Nardone v. United States, 308 U.S. 338, 341, 60 S.Ct. 266, 84 L.Ed. 307 (1939), Wilson v. United States, 218 F.2d 754, 757 (10th Cir. 1955), Lotto v. United States, 157 F.2d 623. 626 (8th Cir. 1946), and he has not met this burden in this case. The Government says that its undercover agents would be “blown,” to use the vernacular, if they came to the surface to sign complaints as soon as an offender is detected and that the Government is entitled to maintain their usefulness by delaying arrests which would reveal them as agents. We believe this position to be both sound and substantial, for the Government, as the representative of the public, has a vested interest in operating at maximum efficiency in its enforcement of the law. Public interest in the proper administration of justice permits, if indeed it does not require, the rights and interests of the public to be kept as well protected and free from prejudice as is possible, so long as that protection and freedom is consistent with the rights of an accused. Use of undercover agents is a necessary and accepted police practice, and the interest of the Government in keeping an agent’s identity secret for a reasonable period is a legitimate basis for delaying the arrest of an individual wrongdoer while the agent is continuing his covert investigations. This court indicated in Nickens, supra, that the statute of limitations is but one, albeit the ultimate, bar to prosecution. Our view of the instant case is that it presents neither a due process question nor a case for exercise of our supervisory powers.
Further, since it cannot be seriously argued that the police work wholly independently of the United States Attorney’s office in these matters, it would seem that the acknowledged existence of governmental discretion in deciding whether or not to prosecute a given case tends to rebut appellant’s claim of right to immediate arrest. We hold that the pre-arrest delay in this case was supported by a commendably legitimate reason. The efficacy of the undercover investigation which revealed appellant as a narcotics trafficker is demonstrated by the fact that 102 arrest warrants were issued for narcotics violations from this one investigation alone. To judicially disapprove of the police practice here involved would virtually end effective enforcement of narcotics laws, for surely it is within the realm of common knowledge and common sense that uniformed or otherwise known policemen are unable to penetrate the sub rosa world of the narcotics peddler. Extensive, time-consuming investigations by undercover operatives, who daily risk their lives, are required to get to the retail and wholesale sources of illicit narcotics.6
Since appellant has impeached neither the necessity for nor the investigative activities of Officer Moore, he has, in our opinion, fallen short of establishing his due process claim. As we said, both the absence of a valid reason for pre-arrest delay and the fact of prejudice are necessary to raise the due process claim. Appellant’s claim that when he was arrested his memory of his whereabouts on or the events of October 10 and 11, 1962, was not clear might have found some support had he so testified, but on the record here we cannot say that this human failing, standing alone, has been shown to be of constitutional dimensions.
*709In Ross the respective positions taken by the members of the sitting division were extensively canvassed. The majority view there turns finally on the lack of adequate corroboration of the testimony of the undercover police officer. See note 4 of Ross and (3) of the last paragraph of the majority opinion in that case. Even so, Ross left open yet • other cases, each to turn on its own facts. A seven-month delay there was too long, the court said, but a four-month delay might not be. Compare Mackey v. United States, No. 18,525, 122 U.S.App.D.C. -, 351 F.2d 794, decided June 30, 1965.
Thus, no automatic rule of decision was announced in Ross, and if, as the dissenting judge here suggests, we have not applied Ross mechanically, we have a good reason for not doing so: The division of the court which decided Ross failed to follow a long line of decisions of the Supreme Court and of this court, including our own recent decisions in Morgan v. United States, 115 U.S.App.D.C. 310, 319 F.2d 711, rehearing en banc denied, cert. denied, 375 U.S. 884, 84 S.Ct. 158, 11 L.Ed.2d 114 (1963), and Wilson v. United States, supra note 3. Indeed, the Wilson court explicitly stated: “[T]he uncorroborated testimony of a narcotics agent is sufficient to support conviction for violation of the narcotics laws.” As stated in note 3 hereof, this court rejected, by a vote of 6 to 3, rehearing en banc in Wilson, not only on the corroboration phase of the case but also on the lapse of time between the offense and the arrest.
Though we do not consider it necessary to our decision, it should be noted that the narcotics sales for which appellant stands convicted were made, in the presence of Officer Moore, to one Atria Harris, a special employee of the Narcotics Squad. Harris, called as a defense witness, corroborated Officer Moore’s testimony that the sales were made by appellant on the dates in question. Further, although appellant did not testify, his alibi defense was the testimony of his sister to the effect that appellant was in New York visiting her for an approximate two-month period which encompassed the dates of the sales. Obviously, the jury chose to disbelieve appellant’s sister.
The other points raised on appeal merit but short consideration. Appellant was not improperly denied a preliminary hearing since it was his own actions which forced continuance. While, in some circumstances not here present, remedial measures may be sought after an indictment is returned, neither dismissal of the indictment nor reversal of the conviction after a full scale trial is an appropriate remedy, especially where, as here, there is no showing of prejudice. Blue v. United States, 119 U.S.App.D.C. 315, 342 F.2d 894 (1964), cert. denied, 380 U.S. 944, 85 S.Ct. 1029, 13 L.Ed.2d 964 (1965). Appellant was not denied a speedy trial; all post-arrest delay is clearly attributable either to appellant himself or to his counsel. See Rindgo v. United States, 120 U.S.App.D.C. 138, 344 F.2d 523 (1964), cert. denied, 380 U.S. 938, 85 S.Ct. 951, 13 L.Ed.2d 825 (1965). Denial of appellant’s motion for a transcript of the grand jury proceedings was, in the circumstances of this case, entirely proper as there was no showing of particularized need, Pittsburgh Plate Glass Co. v. United States, 360 U.S. 395, 399, 79 S.Ct. 1237, 3 L.Ed.2d 1323 (1959); and, unlike Gordan v. United States, 112 U.S.App. D.C. 33, 299 F.2d 117 (1962), the Government’s case here does not hang by the single thread of one police officer’s testimony. The prosecutor’s rebuttal argument was proper, if somewhat lengthy, and in any event was not objected to at trial.
Finally, we find sufficient evidence in the record to support the convictions on all counts.
Affirmed.
. The transactions were sales of unstamped narcotics (heroin) to a person who had no written order therefor, and appellant was charged with violations of 21 U.S.C. § 174 and 26 U.S.C. § 4704(a) and § 4705(a).
. The fact, as noted later in the opinion, that appellant produced an alibi witness who testified in his behalf would seem to rebut his claim of prejudice and to resolve this issue against him.
. An eight-month delay between offense and arrest was held to be not oppressive in Hardy v. United States, 119 U.S.App.D.C. 364, 343 F.2d 233 (1964), cert. denied, 380 U.S. 984, 85 S.Ct. 1353, 14 L.Ed.2d 276 (1965). Also, in Wilson v. United States, 118 U.S.App.D.C. 319, 335 F.2d 982 (1964), this court refused to grant a rehearing en banc to consider a due process claim founded on a six-month delay between offense and arrest.
. The applicable statute in this case is 18 U.S.C. § 3282, but appellant does not claim that his prosecution was barred thereby.
. To be entirely accurate, it should be noted that an arrest does not toll the statute of limitations. Rather, it is the return of an indictment or the filing of an information which must he done before expiration of the statutory period, and this may occur before as well as after the arrest. Since in this case the arrest occurred first, we limit our consideration accordingly.
. Compare the discussion, pro and con, on the general problem in Ross v. United States, No. 17,877, 121 U.S.App.D.C.-, 349 E\2d 210, decided by this court June 30, 1965.