FERREN, Associate Judge:
A jury convicted appellant, Quinton R. Asbell, of robbery, D.C. Code 1973, § 22-2901, and second-degree burglary, id. § 1801(b).1 After noting an appeal and receiving new appointed counsel, appellant requested, and was denied, a new trial based on a claim of ineffective assistance of counsel. Although many issues have been raised on appeal, most coverage in a basic question: whether appellant’s counsel, whom the trial court found grossly incompetent, prejudiced appellant to the extent of denying him the essence of a substantial defense. We conclude that counsel’s gross incompetence had this effect. We further conclude, however, that this case does not warrant dismissal for lack of a speedy trial; nor does it warrant reconsideration of suppression issues raised — and disposed of favorably to the government — in connection with the effectiveness claim. We thus reverse and remand the case for a new trial.
I.
On September 17, 1975, at approximately 4:00 p. m., two men entered Randolph E. Appenzeller’s trailer, put a gun to his head, then beat, hog-tied, and robbed him of his wallet, keys, ring, and surveying and other equipment. Two days later police arrested appellant for possessing the stolen property. On April 28 and 29, 1976, appellant, then age 17, was tried as a juvenile for receiving stolen goods, D.C.Code 1973, § 22-2205. He [806]*806was acquitted. Less than a month later, police executed a warrant for appellant’s arrest, this time charging participation in the armed robbery itself. On the same day, May 18, 1976, the court appointed counsel for appellant. He remained in custody until July 22, 1976, when he was released on bond. Appellant was indicted on January 26, 1977, and arraigned two weeks later. Largely due to “court congestion” and “institutional factors,” appellant was not tried until July 17 and 18, 1978.2
At trial, Appenzeller identified appellant as one of the robbers and as the individual he had seen in court two years earlier at appellant’s trial for receipt of stolen goods.3 In addition, Edward Massey, Appenzeller’s co-worker, testified that he had seen one of the robbers in custody when the police had called him to identify the stolen property. Although Massey stated that he had been sure of his identification at the time, after three years he “couldn’t swear that [appellant was] the same guy.” He did indicate, however, that appellant looked similar to the individual he had earlier identified. The government then called Sergeant Thomas G. James to testify that appellant had been in police custody when Massey had identified the stolen property and claimed to have recognized one of the robbers. Finally, the government called Detective Lorren D. Leadmon, who testified that appellant, after being arrested and advised of his rights on September 19, 1975, admitted he had gone with the robbers on September 17 but insisted he had stayed in the car while two others had robbed Appenzel-ler.
Appellant was the only witness for the defense. He denied participation in the robbery. He also denied having made any statement about the robbery to Detective Leadmon. On cross-examination, appellant testified that on the afternoon of September 17, he had been at home with his mother. He claimed that he remembered this day because it was his nephew’s birthday. Also on cross-examination, appellant described his activity on September 19. The prosecutor impeached this latter testimony with statements appellant had made at his earlier trial. In addition, the prosecutor was able to impeach appellant’s testimony that he had never seen Appenzeller before the day of the second trial, for Appenzeller had testified against appellant at his first trial. See note 3 supra.
On July 19, 1978, the jury found appellant guilty of robbery and second-degree burglary, while acquitting him of the other charges. On November 13, 1978, the court committed appellant under the Federal Youth Corrections Act. 18 U.S.C. § 5010(b) (1976). He noted an appeal. This court appointed new counsel, who filed a motion for a new trial alleging ineffective assistance of counsel, in violation of Sixth Amendment rights. The court heard the motion on September 24 and 25, 1979, and denied it on November 9, 1979. The court concluded that, although appellant’s trial counsel had been grossly incompetent, his incompetence “ha[d] not caused the defendant actual prejudice by blotting out the essence of a substantial defense.” Consolidated before us now are the appeals from the trial and the denial of the new trial motion.
II.
Appellant bears a heavy burden in attempting to show violation of his Sixth Amendment right to effective assistance of counsel. In Angarano v. United States, D.C.App., 312 A.2d 295, 298 n.5 (1973), rehearing denied, 329 A.2d 453 (1974) (en banc), we adopted the test of Bruce v. United States, 126 U.S.App.D.C. 336, 379 F.2d 113 (1967), that, to establish an ineffective [807]*807assistance claim, a defendant must show “both that there has been gross incompetence of counsel and that this in effect blotted out the essence of a substantial defense either in the District Court or on appeal.” Id. at 339-40, 379 F.2d at 116-17 (footnotes omitted). See, e. g., Tillery v. United States, D.C.App., 419 A.2d 970, 972 (1980); Johnson v. United States, D.C.App., 413 A.2d 499, 502 (1980); Wright v. United States, D.C.App., 387 A.2d 582, 586 (1978). Thus, it is not enough for appellant to show that trial counsel was grossly incompetent; appellant also must show a casual relationship between that incompetence and the failure of the defense.4
In determining whether trial counsel’s performance blotted out the essence of a substantial defense we apply a “totality of the circumstances” test. Tillery, supra at 973 (quoting Oesby v. United States, D.C.App., 398 A.2d 1, 8 (1979)). Thus, even though any one specific error by counsel may not constitute ineffective assistance, “the totality of the omissions and errors” may be sufficient. United States v. Hammonds, 138 U.S.App.D.C. 166, 173, 425 F.2d 597, 604 (1970). In reviewing this totality of circumstances, moreover, we are not limited to considering only the loss of affirmative defenses; ineffective attack on the government’s case-in-chief may result in unconstitutional deprivation of counsel. As we recently stated in Johnson v. United States, supra:
A “substantial defense” ... is not limited to an affirmative defense or the presentation of an alibi defense. A defense may be predicated upon disproving an element of the crime charged or simply discrediting the testimony of the prosecution witness. A substantial defense would be lost, for example, if defense counsel failed to use available prior perjury convictions to impeach the sole prosecution witness, or to use prior inconsistent statements which sharply undercut the witness’ credibility. Such failures could “blot out” a substantial defense even where it would be entirely appropriate for the defense to put on no evidence at all of its own. The defense may rely on the presumption of his innocence and on the government’s obligation to prove each and every element of an offense beyond a reasonable doubt. [Id. at 504-05 (citations omitted).]
III.
The trial court’s conclusion that appellant’s counsel had been grossly incompetent was based on the following findings of fact:
1. Trial counsel failed to conduct a full interview with the defendant to determine all relevant facts known to the defendant.
2. Trial counsel failed to keep the defendant informed of his case or prepare him adequately for trial.
3. Trial counsel failed to conduct a prompt investigation of the case and failed to interview any of the witnesses called by the government.
4. Trial counsel failed to engage in any meaningful discovery with the government with regard to the facts of this case.
5. Trial counsel failed to engage in any meaningful plea discussions with the prosecutor.
[808]*8086. Following the verdict, trial counsel did not submit favorable information to the court for purposes of sentencing.
7. Trial counsel apparently has not retained any records with regard to this case.
We agree that the record supports these findings, as well as the conclusion that trial counsel was grossly incompetent — determinations which the government does not contest. In order to evaluate whether counsel’s gross incompetence prejudiced appellant, we examine the course of the trial in greater detail.
A. “Trial counsel failed to conduct a full interview with the defendant to determine all relevant facts known to the defendant.”
At the hearing on the new trial motion, trial counsel acknowledged that he only had interviewed his client in hallways and courtrooms when both were required to be at the courthouse for some other purpose. Counsel stated that all he had learned from these interviews was appellant’s claim that he had not been present at the robbery. Appellant testified that his counsel never asked him about a possible alibi. In response, counsel testified that he could not recall whether he had asked his client about an alibi.5
As result of trial counsel’s failure to interview his client in depth, counsel learned of appellant’s alibi claim for the first time while the prosecutor was cross-examining appellant. Counsel never had interviewed the witness who appellant claimed would have provided him with an alibi — appellant’s mother. Thus, he did not call her to the stand. Nor did counsel mention an alibi in either his opening or closing statement. It is true that at the hearing on the motion for new trial in September 1979, appellant’s mother acknowledged she no longer could remember whether her son was with her on September 17, 1975, the day of the robbery, and intimated that she could not have remembered even if the hearing had been held at the time of the arrest in May 1976.6 [809]*809She did testify, however, that her grandson had had a birthday party on September 17, 1975; thus, she partially corroborated appellant’s testimony that he remembered he was at home on the day of the robbery because it was his nephew’s birthday.
In closing argument, the prosecutor reminded the jury, without defense objection, that appellant had not called his mother as a witness, despite his claim that she provided him with an alibi. This statement by the prosecutor highlighted the harm to appellant by his own counsel's failure to discover the alibi defense and call appellant’s mother to the stand, even for the limited corroboration she could have provided.
B. “Trial counsel failed to keep the defendant informed of his case or prepare him adequately for trial.”
Trial counsel admitted that he never prepared his client with sample cross-examination and could recall preparing him for direct examination only by asking “what he would say about the matter,” in reply to which “[h]e said he wasn’t there.” Counsel’s own glaring lack of preparation became evident at trial when in full view of the jury, during appellant’s testimony on redirect, counsel asked the court if he could consult with his client. The request was denied.
Unprepared, appellant became confused under cross-examination as to the dates of the alleged incident and his arrest. Moreover, he testified that he had never seen Appenzeller before trial, only to be impeached by the fact that Appenzeller had testified against him at his earlier juvenile hearing. As indicated earlier, when appellant testified that he had been at home with his mother on the day of the robbery, he did so for the first time under the adverse conditions of cross-examination, rather than during his opening testimony. Even with adequate preparation, of course, appellant might have been impeached and the consistency of his story attacked. But here, his total lack of preparation made appellant look especially weak in withholding his alibi until cross-examination; and he was particularly easy prey for the government’s sharp questions on cross-examination.
C. “Trial counsel failed to conduct a prompt investigation of the case and failed to interview any of the witnesses called by the government and “[t]rial counsel failed to engage in any meaningful discovery with the government with regard to the facts of this case.”
By his own admission, trial counsel read the police report of the robbery for the first time while the trial was in progress. Moreover, he admitted that he never interviewed any of the government’s witnesses, even though the prosecutor had offered him the opportunity for discovery.7 Furthermore, although counsel knew the government had a written statement allegedly made by his client, he neither obtained the statement nor filed a motion to suppress it. Finally, despite being appointed more than two years before appellant’s trial, counsel learned only on the morning of trial that his client had been tried and acquitted as a juvenile for receiving the same stolen property for which he presently was charged with robbery. Counsel remained ignorant in spite of the fact that the Affidavit in Support of an Arrest Warrant contained the relevant information.
As a result of trial counsel’s lack of investigation, he learned for the first time at trial that the complaining witness had identified his client at the juvenile hearing. Thus, counsel never took advantage of the prior testimony of this witness for impeachment purposes, despite the fact that he [810]*810could have used this testimony to question the certainty of his identification.8
Counsel’s failure to apprise himself of the facts of appellant’s juvenile hearing became evident to the jury at least by the second day of trial. After the government had completed its cross-examination of appellant, having seriously impeached him with the use of his statements at the earlier proceeding, defense counsel asked for a five minute recess to review the documents on which the government had relied. Despite the fact that counsel had been supplied with these documents the day before, he told the court, “I haven’t seen them.” Responding to the court’s question whether he denied having received the documents the previous day, counsel stated:
I said I haven’t seen it recently. I didn’t finish my statement. I said I haven’t seen it. I am not aware of the contents of it at the moment. I don’t know what he is talking about. That’s the problem. I’m sorry.
Counsel received a few minutes to read the transcript, without a recess, in front of the jury.
D. Trial Counsel’s performance, “blotted out the essence of a substantial defense.”
Given the “totality of the circumstances,” Tillery, supra at 973; Oesby, supra at 8, the trial court erred in concluding that, although trial counsel was “grossly incompetent” (which the government does not contest), he “has not caused the defendant actual prejudice by blotting out the essence of a substantial defense.” See Angarano, supra at 298 n.5; Bruce, supra at 339-40, 379 F.2d at 116-17. On this record, that statement is inherently contradictory. As a result of counsel’s failure to conduct a full client interview to investigate the case, to engage in meaningful discovery, or to prepare appellant adequately for trial, appellant received no defense whatsoever.9
We begin by noting the government’s evidence was not so strong that minimally competent counsel, performing elementary defense responsibilities, could not have precipitated an acquittal. Appenzeller identified appellant in court as one of the robbers, but Massey was not certain and Sergeant James could not confirm for sure that Massey had identified appellant earlier. Detective Leadman testified that appellant had admitted being present at the scene, but appellant, taking the stand in his own defense, denied he had ever said so. On cross-examination, moreover, appellant offered an alibi. The jury, therefore, was confronted by a typical case of strong but not conclusive evidence against appellant.
Any defense effort, to be successful, had to discredit Appenzeller’s identification and to refute appellant’s alleged admission to Detective Leadman. Significantly, both avenues at least had some promise. The weakness of Appenzeller’s previous identification of appellant at the juvenile hearing was classic impeachment material for discrediting the in-court identification over two years later. See note 8 supra. Coun[811]*811sel, however, altogether failed to attempt such impeachment. Counsel, in fact, failed even to discuss Appenzeller’s juvenile hearing testimony with appellant, a lapse obviously contributing to appellant’s own testimony — for which he was impeached — that he had never seen Appenzeller before the present trial.
Despite the weakness of appellant’s alibi — his principal defense against his admission alleged by Detective Leadman — appellant still did have an alibi defense which to some extent his mother could have corroborated. See Part III. A. supra. Counsel, however, learned about the alibi for the first time during his client’s cross-examination and even then did not call the mother (whom he never had interviewed) at least to testify that her grandson had a birthday on September 17, 1975 — a fact appellant asserted as part of his alibi. This lapse by counsel not only weakened appellant’s alibi defense but also gave the government an opportunity, in closing argument, to remind the jury that appellant had not called his mother to testify, despite claiming she could provide significant corroboration.
Taken together, these two lapses — failures to contest the government’s case with available impeachment, see Johnson, supra at 505, and to present appellant’s alibi defense — “blotted out the essence of a substantial defense.” See Angarano, supra at 298 n.5; Bruce, supra at 339-40, 379 F.2d at 116-17.
We recognize that when a record shows that counsel has performed fundamental criminal defense functions, though with a grossly incompetent lapse, the defense bears a substantial burden to show that the lapse, on the particular record at issue, materially lessened the opportunity for acquittal. See Wright, supra at 585-87; note 4 supra. This heavy burden is justified by the fact that when counsel performs these functions — a comprehensive client interview, investigation, discovery from the government, and preparation of the client for trial — the court ordinarily can perceive a cogent defense strategy against which the alleged lapse can be measured.
When, however — as here — counsel’s gross incompetence is virtually a default in fundamental defense functions, a court can be less sure that counsel’s lapse did not materially lessen the opportunity for acquittal, for the court is evaluating the impact of gross incompetence without any objective reason for assuming that sensible tactical judgments underlay counsel’s basic approach. See Wright, supra at 585-87; note 4 supra. In this situation, therefore, a court confronted with gross incompetence must be much more cautious in permitting itself to conclude that no substantial defense has been blotted out. As in this case, the failure to use available impeachment of a key government witness, as well as to present the defendant’s affirmative defense, is enough to warrant our conclusion that counsel’s gross incompetence blotted out the essence of a substantial defense. Were we to conclude otherwise, we would be substituting ourselves for a jury deprived of material defense evidence that was available to defense counsel at the time of trial. We cannot properly do so.
The trial court did not evaluate counsel’s gross incompetence from this perspective. In fact, the court focused primarily, if not solely, on the facts supporting appellant’s affirmative defense, without due regard to the potential defense attack on the government’s case-in-chief (e. g., Appenzeller’s identification). Accordingly, we cannot accept the trial court’s analysis. Appellant’s conviction must be reversed for violation of his Sixth Amendment right to effective assistance of counsel.
IV.
Three issues remain: whether reversal mandates dismissal of the indictment for violation for appellant’s Fifth Amendment right to due process (based on preindictment delay), or of his Sixth Amendment right to a speedy trial; and, if not, whether on remand for a new trial appellant should be permitted to file a motion to suppress his statement to the police and his identification by the complaining witness.
[812]*812A. Due Process
Appellant was arrested for robbery and burglary in May 1976, eight months after the incident giving rise to the charge (and one month after his acquittal for possession of stolen property based on the same incident). The court appointed counsel on the day of arrest. Appellant was indicted eight months later in January 1977. On appeal, he alleges that this 16-month preindictment delay — analogous to deprivation of the right to a speedy trial — violated due process.
The Supreme Court has acknowledged the validity of a number of reasons why the government may wish to proceed cautiously with arrest and/or indictment, most notably the concern that a person not be charged without conscientious scrutiny of the facts. United States v. Lovasco, 431 U.S. 783, 791-95, 97 S.Ct. 2044, 2049-2051, 52 L.Ed.2d 752 (1977). Thus, preindictment delay is not inherently unfair. To prevail on this argument, appellant must show at a minimum that he actually was prejudiced by the delay and that the government’s reasons were unjustified. Lovasco, supra at 790, 97 S.Ct. at 2048; Smith v. United States, D.C.App., 414 A.2d 1189, 1194 (1980); cf. United States v. Alston, D.C.App., 412 A.2d 351, 359 (1980) (en banc) (applying a similar analysis to appellate delay).
In the present case, the government’s reasons for deferring arrest and indictment for robbery and burglary until after appellant’s acquittal on the possession-of-stolen property charge are not self-evident; no reason appears as to why the government may have needed time to develop additional evidence. On the other hand, no unseemly motives can be ascribed to the government on this record. Nor has appellant shown prejudice from pre-arrest or pre-indictment delay. He was incarcerated for only two months during this period, and he has not been able to demonstrate that, but for such delay, he could have provided a credible alibi witness, see note 6 supra, or other defense. Nor is there a basis to believe that competent, new counsel for the defense will be prejudiced by this particular lapse of time. On this record, therefore, we perceive no due process violation.
B. Speedy Trial
The speedy-trial issue is more complex. Appellant was not brought to trial until 18 months after indictment and 26 months after arrest for robbery and burglary.10 Because this delay between arrest and trial was more than a year, appellant has established a prima facie Sixth Amendment violation. Branch v. United States, D.C.App., 372 A.2d 998, 1000 (1977). Accordingly, the burden has shifted to the government to prove that no constitutional violation has occurred, using the criteria prescribed in Barker v. Wingo, 407 U.S. 514, 530-33, 92 S.Ct. 2182, 2191-2193, 33 L.Ed.2d 101 (1972): length of delay, reasons for delay, assertion (or nonassertion) of the right, and prejudice.
1. Assertion of the Right
Although each of these factors is important, the Court stated in Barker that “barring extraordinary circumstances,” it would be extremely reluctant to find a speedy trial violation when there has been no timely assertion of the right. Id. at 536, 92 S.Ct. at 2194. Such assertion not only is important in itself but also is significant for its relationship to the other three factors.
Whether and how a defendant asserts his right is closely related to the other factors we have mentioned. The strength of his efforts will be affected by the length of the delay, to some extent by the reason for the delay, and most particularly by the personal prejudice, which is not always readily identifiable, that he experiences. The more serious the deprivation, the more likely a defendant is to com[813]*813plain. The defendant’s assertion of his speedy trial right, then, is entitled to strong evidentiary weight in determining whether the defendant is being deprived of the right. We emphasize that failure to assert the right will make it difficult for a defendant to prove that he was denied a speedy trial. [Id. at 531-32, 92 S.Ct. at 2192.]
This court, accordingly, has placed great emphasis on assertion of the right. For example, in Jefferson v. United States, D.C.App., 382 A.2d 1030, 1032 (1978), we noted: “To the extent that prejudice may be presumed from the existence of unresolved charges with the attendant anxiety and concern, this inference is substantially weakened by appellant's failure to assert his right to a timely trial . . .. ” Accord, Smith v. United States, D.C.App., 379 A.2d 1166, 1167 (1977). Similarly, in Day v. United States, D.C.App., 390 A.2d 957, 973 (1978), the failure of the accused to demand a speedy trial was a significant factor in our conclusion that a delay which had extended beyond 32 months had not deprived the accused of his constitutional right to a speedy trial. In contrast, in Bethea v. United States, D.C.App., 395 A.2d 787, 792-93 (1978), and in United States v. Ellis, D.C.App., 408 A.2d 971, 973 (1979), we emphasized assertions of the right in reversing the convictions for speedy trial violations.
In this case, appellant did not demand a speedy trial, and yet he cannot be penalized for the failure of incompetent counsel to do so. See Barker, supra 407 U.S. at 536, 92 S.Ct. at 2194.11 Accordingly, as we apply the other three factors, we must be alert to whether competent counsel could have been expected to request an earlier trial.
2. Length of Delay
Computation of the length of delay begins with the date of arrest. Dillingham v. United States, 423 U.S. 64, 65, 96 S.Ct. 303, 46 L.Ed.2d 205 (1975) (per curiam). Here, appellant was arrested for armed robbery in May 1976, 26 months before trial. He had been arrested eight months earlier for receiving stolen property in the same transaction, a fact suggesting that, in the absence of manifest reasons why the government brought charges sequentially instead of concurrently, the significant date for calculating delay was September 19, 1975, 34 months before trial.12 We do not resolve whether calculation should begin from May 1976 or September 1975; solely for the sake of argument we assume a 34-month period.13
3. Reasons for Delay
The reasons for the government’s eight-month delay between arrest and indictment for robbery and burglary are no more clear than the reasons for the previous eight-month delay between arrests. See Part IV. A. supra; note 10 supra. Although there is no evidence that the government acted on the basis of improper motives, there is also no evidence that the government needed this additional time to develop its case. Accordingly, these initial periods of delay are chargeable to the government. Even after indictment, the 18-month delay before trial was substantial and, aside from seven weeks, see note 2 supra, was due to “court congestion” and “institutional factors” attributable to the government (though weighed less heavily than purposeful delay). [814]*814Barker, supra 407 U.S. at 531, 92 S.Ct. at 2192; Day, supra at 965.
4. Prejudice
In Barker, supra, the Supreme Court “expressly rejected the notion that an affirmative demonstration of prejudice was necessary to prove a denial of the constitutional right to a speedy trial.” Moore v. Arizona, 414 U.S. 25, 26, 94 S.Ct. 188, 189, 38 L.Ed.2d 183 (1973) (per curiam). Moreover, in holding that a delay of more than a year established a prima facie Sixth Amendment violation, Branch, supra at 1000, we established that such delay must be presumed prejudicial, and that the longer the delay, the heavier the government’s burden will be to prove the contrary. Id. Nonetheless, we also have held that the government can meet this burden without introducing independent evidence. Day, supra at 971. “The government is entitled to argue both the objective facts of record and inferences to be drawn from a defendant’s failure to assert particular prejudice.” Id. Thus, although the government has the burden of proof here, we must acknowledge that if the defendant can point to no prejudice— and can show no other reason why competent counsel would have asserted the right to an earlier trial — the government will have met its burden; such “significant delay alone, chargeable to the government but not the result of a deliberate effort to obtain a tactical advantage,” does not violate the Sixth Amendment right to a speedy trial. Id. at 973.
A court is forced to rely on presumptions of prejudice from delay as such, discounted by counter-inferences of no prejudice when none is alleged, because of the practical difficulty of proving or disproving prejudice in most cases. When a key witness dies or evidence is lost, prejudice may be obvious; but when a witness’s memory allegedly fades, or an appellant allegedly would have been better able to prepare the defense if he or she had not been incarcerated, the court necessarily is in a realm of speculation. See Barker, supra 407 U.S. at 532, 92 S.Ct. at 2192; Branch, supra at 1002.14
In this case, we have the problem of faded memory. The only concrete example of prejudice from delay is the asserted inability of appellant’s mother to remember whether he was at his nephew’s birthday party on September 17, 1975, the day the robbery occurred. Although she could confirm that the birthday was September 17, it is at best unclear whether, if appellant had received a speedier trial, his mother could have remembered whether he had been at the party. There is reason to doubt she could have remembered even as early as April or May 1976, when appellant was tried on the stolen property charge. See note 6 supra.15 Furthermore, one of the government’s witnesses, Massey, was not altogether sure of his identification of appellant at trial. If trial had been held earlier, it is just as likely that Massey would have been more, not less, positive in .his identification.16 Because appellant made no other specific allegations of prejudice, we conclude that the government has met its burden to show no reasonable possibility that appellant was prejudiced by the lengthy delay before trial. See Day, supra at 973.
[815]*8155. Conclusion as to Speedy Trial
Although the incompetence of trial counsel makes this case atypical, we are left with a typical fact situation to weigh. There was substantial delay in bringing appellant to trial — 26 to 34 months — almost all of which must be weighed against the government for institutional, not purposeful, reasons. While we cannot penalize appellant for counsel’s failure to assert the right, we perceive no reason on this record — including evidence and argument at the post-trial hearing — indicating that competent counsel would have done so. The only prejudice alleged amounted to pure speculation about the loss of a favorable memory by appellant’s mother. We hold, accordingly, that the government has carried its burden of demonstrating no speedy trial violation warranting dismissal. See Day, supra at 973.
V.
We turn, finally, to the question whether appellant may now file motions to suppress Appenzeller’s eyewitness identification and appellant’s statement to the police.
In support of the motion for new trial, appellant sought to show that counsel’s failure to file suppression motions was another indication of ineffective assistance of counsel. In doing so, appellant felt obliged to demonstrate only that there was a “likelihood” or “possibility” of success, such that effective counsel would have filed them; he did not perceive an obligation, and thus did not introduce evidence, to prove that the motions, if timely made, would have been successful.
At the motion hearing, appellant undertook to prove too little. Even if we assume that no responsible criminal defense lawyer would have failed to file suppression motions on the facts here, it does not follow that this failure helped “blot out the essence of a substantial defense” — unless the court would have granted the motions and thus kept the evidence from the jury. If the motions, pressed in the most effective way possible, would still have been denied, any incompetence in failing to pursue them would have been irrelevant, for it could not have influenced the fact-finder. Accordingly, if a defendant seeks a new trial on the ground of incompetent counsel’s failure to file a suppression motion, the defendant must be prepared at the time of the motion hearing to introduce whatever evidence will be necessary to succeed with suppression; otherwise, the point will fail, and the ruling will become the law of the case. See Duddles v. United States, D.C.App., 399 A.2d 59, 64 (1979); Wheeler v. United States, D.C.App., 300 A.2d 713, 715 (1973); Jenkins v. United States, D.C.App., 284 A.2d 460, 463-64 (1971); cf. Smith v. United States, D.C.App., 406 A.2d 1262, 1263-64 (1979) (unsuccessful suppression motion before original prosecution was dismissed without prejudice is law of the case for second prosecution).17
In contrast with the trial itself, where appellant, because of grossly incompetent counsel, was not able to develop his case before the jury, appellant had an opportunity at the hearing on the new trial motion, with new counsel, to develop a complete record on which the court could rule as to the validity of a suppression motion. It would be a waste of judicial resources for a court to grant a new trial solely or partially on the ground that incompetent counsel failed to file a nonfrivolous — or even a highly persuasive — suppression motion, and then for it to turn out, after still another [816]*816hearing, that the motion is ultimately denied.18
In this case, at the hearing on the new trial motion, appellant did not introduce evidence on the suppression issues— eyewitness identification and appellant’s statement to the police — that would have amplified or changed the record created on these matters when appellant was represented by grossly incompetent counsel. For example, because appellant did not call for testimony by any of the police officers who had been involved in taking appellant’s statement or identification, the court was forced to rule on the basis of the officers’ testimony at trial. We must presume, therefore, that additional testimony would have added nothing.
On this record, we perceive no trial court error in finding no merit to a motion to suppress identification, for there was sufficient evidence of reliability to outweigh any suggestiveness. See Manson v. Brathwaite, 432 U.S. 98, 97 S.Ct. 2243, 53 L.Ed.2d 140 (1977). Nor was there error in finding no evidentiary basis to suppress appellant’s statement to the police.
VI.
In summary, we reverse appellant’s convictions for deprivation of his Sixth Amendment right to effective assistance of counsel. Dismissal for denial of due process from preindictment delay, or for lack of a speedy trial, is unwarranted. Accordingly, we remand the case for a new trial. However, the trial court properly ruled that there were no bases for motions to suppress the identification of appellant or his statement to the police. Those rulings are the law of the case.
Reversed and remanded.