1350,1352 (5th Cir. 1973). Due regard must be given to the trial judge’s opportunity to view the demeanor of the witnesses and assess their credibility, Wright v. North Carolina, 483 F.2d 405, 408 (4th Cir. 1973), cert. denied, 415 U.S. 936, 94 S.Ct. 1452, 39 L.Ed.2d 494 (1974).
Parker’s arguments on appeal are a substantial repetition of those made to the trial judge and rejected by him. Parker urges this court to reassess the evidence presented to the trial court and reach a conclusion contrary to that made below. His arguments, however, fail to demonstrate clear error by the trial court, and, thus, the trial court’s finding of voluntariness is affirmed.3
The Warrantless Arrest
Parker also contends that the government agents’ failure to obtain an arrest warrant vitiated his arrest and rendered his subsequent confession illegal. Parker does not dispute that the agents had probable cause to arrest him, but asserts that they should have obtained a warrant in the approximately 34 hours between the time that they became aware of his whereabouts and the time of the arrest. This argument has no merit. While it is preferable for law enforcement officers to obtain arrest warrants where feasible, Beck v. Ohio, 379 U.S. 89, 96, 85 S.Ct. 223, 13 L.Ed.2d 142 (1964); Wong Sun v. United States, 371 U.S. 471, 479-82, 83 S.Ct. 407, 9 L.Ed.2d 441 (1963), an arrest supported by probable cause should not be invalidated solely because the officers failed to secure a warrant, Gerstein v. Pugh, 420 U.S. 103, 113, 95 S.Ct. 854, 43 L.Ed.2d 54 (1975); United States v. Hofman, 488 F.2d 287 (5th Cir. 1974). Although Parker argues that the officers had ample opportunity to obtain an arrest warrant, this argument, even if true, does not invalidate his arrest, United States v. Burnett, 526 F.2d 911 (5th Cir.), cert. denied, 425 U.S. 977, 96 S.Ct. 2179, 48 L.Ed.2d 801 (1976).4
The Prosecutor’s Closing Argument in the Case of Parker
Finally Parker argues that his conviction on Count IV should be reversed on the ground that the prosecutor improperly commented on his failure to .testify. Parker had walked in front of the jury solely for the purpose of displaying his gold capped tooth, a feature of his appearance which none of the eyewitnesses had testified about in identifying him as the robber.
5 Although the prosecutor’s statement did not directly deal with Parker’s failure to take the stand, it did refer to his silence and, thus, was improper.
Griffin v. California, 380 U.S. 609, 85 S.Ct. 1229, 14 L.Ed.2d 106 (1965). While it was entirely appropriate for the prosecutor to argue to the jury that Parker’s tooth might have been capped after the robberies took place, it was improper for him to comment on what Parker “failed to state” or “didn’t tell us.” The error, however, does not require reversal of the conviction because it was harmless beyond a reasonable doubt.
Chapman v. California, 386 U.S. 18, 24, 87 S.Ct. 824, 17 L.Ed.2d 705 (1967). The comment was not extensive, it did not stress any inference of guilt from Parker’s silence, and there was no substantial evidence that could have supported an acquittal.
Anderson v. Nelson, 390 U.S. 523, 88 S.Ct. 1133, 20 L.Ed.2d 81 (1968);
Scarborough v. Arizona, 531 F.2d 959, 962 (9th Cir. 1976).
The Evidence of Faithe’s Heroin Addiction
Faithe raises four contentions on this appeal none of which is sufficient to warrant reversal of his conviction.
3
Since we find that the confession was voluntary, there is no merit to Parker’s contention that the evidence admitted at his trial of Count IV was tainted by the involuntary confession.
4
Since we find that there was no Fourth Amendment violation, there is no basis on which Parker can argue that the evidence at the trial of Count IV was tainted.