Appellant, found guilty after a bench trial of assault with intent to kill, malicious disfigurement, arson, and destruction of property, contends that the trial judge abused her discretion in refusing to hold a hearing on his post-conviction motion alleging ineffective assistance of counsel. We affirm.
The government’s theory, presented through the witness Deone Adams, was that appellant enlisted Adams’ help in setting fire to two buildings, after which appellant unexpectedly threw gasoline at Adams and ignited it. The apparent explanation for this assault was Adams’ demand that appellant pay him some money which appellant owed him.
Appellant’s post-conviction motion related chiefly to trial counsel’s failure to call certain witnesses. First, with his motion appellant presented affidavits from three witnesses who he claimed would have supported his testimony that he was at Massachusetts and Southern Avenues, S.E., more than forty blocks away, at the time of the arson and assault.1 The trial judge concluded, in part, that the proffered alibi testimony “would be merely cumulative to that of the defendant.” Ordinarily this would not be a reason to deny a hearing: corroborative witnesses may cause a factfinder to credit testimony by a single witness (a self-interested defendant) whose testimony would otherwise fail to persuade. But this case is different. The judge as trier of fact found appellant’s defense at trial to be “inherently incredible.” Specifically, appellant had testified that he lent Adams a gasoline can (Adams had some lawn work to do), drove him to a gas station and bought gas for him, then dropped him off at Massachusetts and Southern Avenues. Less than an hour later, his body seriously burned, Adams supposedly rejoined appellant and appellant drove him to a hospital. Appellant and Adams, the judge explained:
did not agree to meet at that location [i.e., Massachusetts and Southern Avenues] ... nor did the defendant tell Mr. Adams how long he would be there. Mr. Adams is ... alleged to have walked, or in some way traveled, from this location to the location of the arson, in excess of forty city blocks in that span of approximately forty five minutes, set both buildings and himself afire and retum[ed] to a location where he did not know the defendant would be.... Mr. Adams, ... according to the defendant, traveled a considerable distance with severe burns over one half of his body to arrive back at a location where he had no idea the defendant would be.[2]
Having thus previously rejected appellant’s alibi defense as unbelievable, the judge, in denying the post-conviction motion, concluded that additional testimony that Adams had rejoined appellant at Massachusetts and Southern Avenues created no “reasoned probability” that she would have evaluated the defense differently; and appellant therefore had not shown the necessary prejudice under Strickland v. Washington, 466 U.S. 668, 104 S.Ct. 2052, 80 L.Ed.2d 674 (1984), to establish ineffective assistance of counsel.
This court, of course, may not substitute its view of the plausibility or implausibility of the defense for that of the trier of fact. Even after a jury trial, “the trial judge, who has ... watched the evidence unfold, is in a *65far better situation than an appellate court to determine whether there is any appreciable possibility that a hearing could establish ... prejudice to the defendant in the Strickland sense.” Sykes v. United States, 585 A.2d 1335, 1340 (D.C.1991). Here, not only the trial judge but also the trier of fact has concluded that testimony from the proffered alibi witnesses, even if consistent with their affidavits, would not create a reasonable probability of a different outcome. Strickland, supra. That is dispositive of appellant’s claim.
Appellant’s post-conviction motion further contained the affidavit of Daniel Botts, an off-duty firefighter who stated that he had seen Adams, on fire, backing out of one of the two buildings appellant and Adams were charged with having torched.3 According to appellant, Botts’s testimony would have impeached Adams’ testimony that appellant pulled up in his car and picked up Adams moments after the latter tumbled out of the building. Botts’s affidavit, however, assuming he testified in accordance with it, reveals no inconsistencies with Adams’ testimony sufficient for us to say that the judge abused her discretion in denying a hearing.4 Botts did not claim to see how the fires had started, or how Adams had come to be set on fire. Botts was not in a position to rule out appellant’s presence at the scene or to refute Adams’ testimony that appellant had picked him up in his car, since Botts conceded (para. 5 of his affidavit) that he had gone into the second building that was on fire to look for occupants. Finally, Botts provided no logic for what the judge as factfinder found to be appellant’s unbelievable defense of an unplanned rendezvous forty blocks from where Adams had purportedly set himself afire.
The trial judge, therefore, concluded that Botts’s assertions even if credited were not such as to create a reasonable probability of a different outcome under Strickland. As emphasized, the judge made that determina-lion as the person who had been the trier of fact cat trial. In these circumstances, the judge was within her discretion in refusing to hold an evidentiary hearing on the Botts proffer. Gregg v. United States, 395 A.2d 36, 39 (D.C.1978) (motion may be denied without hearing where claims, even if true, do not entitle movant to relief).
Appellant’s remaining claims of ineffectiveness likewise do not persuade us that the judge improperly denied a hearing on the motion. In the absence of any proffer of expert testimony about the burn patterns of fires or the so-called backdraft theory on which appellant relied, the judge could properly conclude that the claim of trial counsel’s deficiency in not calling such an expert was “vague and conclusory.” Id. Moreover, the judge could fairly reject without a hearing the claim that counsel had failed adequately to cross-examine Adams about his plea-bargain.5
Affirmed.
. Appellant claimed in an affidavit of his own that he had advised his trial counsel "of various witnesses that could establish my whereabouts at the time of the fire,” but that counsel had failed to contact these witnesses.
. Moreover, the judge pointed out, appellant when arrested had told Detective DuVall a totally different story of how Adams had come to be burned.
. The trial judge’s mistaken belief that Botts had not identified Adams is immaterial; there was no dispute that Adams was at the scene of the fires.
. Indeed, Botts’s affidavit confirmed Adams’ testimony that he had “backed” out of the door to the building.
.The argument that trial counsel elicited material admissions from his own client before the judge as factfinder was not raised below, and in any event has no merit.