McMILLIAN, Circuit Judge.

Louie Co Gunter appeals from a final judgment entered in the District Court for the Eastern District of Arkansas upon a jury verdict finding him guilty of two counts of interstate transportation of a stolen motor vehicle (counts I and III) in violation of 18 U.S.C. § 2312 and two counts of selling and disposing of a stolen motor vehicle (counts II and IV) in violation of 18 U.S.C. § 2313. The trial court sentenced appellant to three terms of six months imprisonment on counts I, II and III, to be served concurrently. The trial court suspended sentence as to count IV and placed appellant on thirty months probation to begin on the expiration of the prison terms.

For reversal appellant argues that the trial court erred in (1) refusing to dismiss the indictment, (2) improperly assuming the role of an advocate during the course of the trial, (3) granting the prosecution a continuance in order to develop additional evidence, (4) refusing to grant appellant's motion for judgment of acquittal, and (5) improperly conducting an evidentiary hearing in the absence of appellant. Appellant further argues that the evidence was insufficient to support the verdict.

For the reasons discussed below, we affirm the judgment of the trial court.

FACTS

This case involves the sale and delivery of two 1977 Lincoln Continental Mark V automobiles. The theory of the prosecution was that the cars were stolen in Michigan and that appellant then sold the cars through a third party, A.L. Scott, to individuals in Arkansas and drove the cars from Michigan to Arkansas.

Car # 1, VIN (Vehicle Identification Number) 7Y89A970966, was the car involved in counts I and II. Bobby Gene Davis bought this car from a Lincoln dealership in Detroit, Michigan, on September 2, 1977. Davis, an Oklahoma resident, was in Detroit visiting his brother. Davis reported the car was stolen from his brother's driveway on September 6, 1977. Davis had left the car papers in the glove compartment but obtained photocopies from the dealership. The car's VIN was written on the saleslip from the dealership.

At the end of September 1977, in Arkansas, Roger Burke bought car # 1 from a man who identified himself as "Mr. Gunter." Burke testified that appellant looked like "Mr. Gunter." The sale had been arranged through A.L. Scott. Gunter knew Scott because they had worked together on a construction project in Arkansas in 1975; Scott was a business acquaintance of Burke's. "Mr. Gunter" gave Burke a Michigan certificate of title which indicated the owner was a Michael Gunter, of 6148 Commonwealth, Detroit, Michigan. Burke attempted to register the car in Arkansas and discovered that the Michigan title was invalid. An Arkansas State Police investigation revealed that the car's VIN was 7Y89A970966, matching the VIN of the car stolen from Bobby Davis.

Car # 2, VIN 7Y89A852467, was a Ford Motor Company car assigned to company executive John Sattler for his personal use. Sattler had made arrangements to pick up the car at the Detroit airport upon his return from a business trip to California in July 1977. Sattler arrived at the airport but was unable to find his car.

In late August 1977, Beverly Yates purchased car # 2 in Detroit. Yates testified that she purchased the car from a black man in his late 20's, about 5'8" tall and weighing about 145 pounds. She further testified that she had never seen appellant and was unable to remember the name of the man who sold her the car. Yates' car registration papers reflect that the car's VIN was 7Y89A848547. She further testified that the car was stolen on September 29, 1977.

In early October 1977, Boyce Cranford purchased car # 2 from a man who identified himself as "Robert Young." Cranford was a business partner of Roger Burke and similarly acquainted with A.L. Scott. Cranford was interested in the same kind of car deal. The sale was arranged through Scott. Cranford testified that a man who identified himself as "Robert Young" gave him a Michigan registration, a Michigan certificate of title and a no-fault insurance form. The VIN on these papers was 7Y89A848547. Cranford was unable to identify the man who sold him the car but, in response to questions asked by the trial court, described the man as black, 5'10" tall, rather thin, relatively small and very nervous.

An official from the Michigan Department of State testified that Cranford's Michigan title, like Burke's, was invalid. In addition, William T. Bowling, a retired employee of the National Automobile Theft Bureau, testified that he examined car # 2 and found the true VIN was 7Y89A852467, matching the VIN of the company car originally assigned to Sattler. Car manufacturers evidently place a duplicate VIN on a relatively inaccessible part of a car, thus making the location and alteration of this VIN more difficult.

Scott's identification testimony was less than positive. Scott testified that appellant did not look much like Gunter, that he had not seen Gunter for more than two years, that he had worked with Gunter about a year in 1975, and that appellant had changed a lot if he was Gunter. In response to questions asked by the trial court, Scott testified about his work experience with Gunter, the employer (Highway Dump Haulers), and how the sales were arranged.

By this time it was about 3:30 p. m. on the first day of trial. The trial court granted the prosecution a brief continuance until 11:00 a. m. the following day to develop additional identification evidence. At 11:40 a. m. the next morning, the trial court met in chambers with the prosecutor and the defense counsel. The subject of discussion was the additional identification evidence sought to be introduced by the prosecution. Trial resumed at approximately 12:15 p. m. FBI agent Charles Poplinger testified that he had interviewed appellant in Detroit and that during the interview appellant provided his Social Security number (250-46-1843) and his address as 6148 Commonwealth, Detroit, Michigan. This was the address on the invalid Michigan title given by "Mr. Gunter" to Roger Burke. Marilyn Johnson, the secretary-treasurer and accountant of Highway Dump Haulers, testified as the business records custodian of that company and produced a W-4 tax withholding form for "Louie C. Gunter," of a local Arkansas address, Social Security number 250-46-1843.

The jury found appellant to be guilty on all four counts. This appeal followed.

I. Dismissal of Indictment

Appellant argues that the trial court erred in refusing to dismiss the indictment. Appellant argues that the grand jury did not have probable cause to issue the indictment because none of the witnesses before the grand jury identified appellant as the perpetrator of the crimes under investigation. We disagree. Appellant failed to raise this challenge to the indictment before trial as required by Fed.R.Crim.P. 12(b)(2). More importantly, appellant cannot challenge an indictment valid on its face on the ground that the grand jury acted on the basis of inadequate or incompetent evidence. United States v. Calandra, 414 U.S. 338, 345, 94 S.Ct. 613, 618, 38 L.Ed.2d 561 (1974); Costello v. United States, 350 U.S. 359, 363, 76 S.Ct. 406, 408, 100 L.Ed. 397 (1956). Furthermore, A.L. Scott identified appellant by name in his testimony before the grand jury. It cannot be said that the grand jury in the present case indicted "a person totally unknown and as yet unconnected by any known evidence with the offense." United States ex rel. Curtis v. Warden of Green Haven Prison, 329 F. Supp. 333, 335 (E.D.N.Y. 1971), aff'd, 463 F.2d 84 (2d Cir. 1972). Cf. United States ex rel. Mouquin v. Hecht, 22 F.2d 264, 265 (2d Cir. 1927) ("The jurors do not indict the man who committed the crime, but him described in the evidence before them. . . . They are to be understood, therefore, as indicting the persons described in the testimony, if doubt arises. Hence, if it be shown that the witnesses described the person arrested, he is the person indicted."), cert. denied, 276 U.S. 621, 48 S.Ct. 301, 72 L.Ed. 736 (1928).

II. Trial Judge as Advocate

Appellant next argues that the trial judge improperly assumed the role of an advocate on behalf of the prosecution during the course of the trial. See United States v. Lanham, 416 F.2d 1140 (5th Cir. 1969). The prosecution contends that the trial judge in questioning the witnesses was merely discharging his duty to clarify the witnesses' testimony. E. g., United States v. Harris, 546 F.2d 234, 238 (8th Cir. 1976); United States v. McColgin, 535 F.2d 471, 474-75 (8th Cir.), cert. denied, 429 U.S. 853, 97 S.Ct. 145, 50 L.Ed.2d 128 (1976); Scruggs v. United States, 450 F.2d 359, 361-63 (8th Cir. 1971), cert. denied, 405 U.S. 1071, 92 S.Ct. 1521, 31 L.Ed.2d 804 (1972); Kramer v. United States, 408 F.2d 837, 841 (8th Cir. 1969); Ray v. United States, 367 F.2d 258, 260-63 (8th Cir. 1966), cert. denied, 386 U.S. 913, 87 S.Ct. 863, 17 L.Ed.2d 785 (1967). Further, the prosecution notes that appellant made no objection to the trial judge's questioning of the witnesses and the trial judge expressly cautioned the jury in the instructions that his comments or questions were not intended to indicate his view of the facts of the case.

We note preliminarily that we must consider appellant's allegation of error under the plain error rule. However, we do understand why defense counsel was reluctant to make objections during trial and thus risk antagonizing the trial court and alienating the jury. Further, we do not consider the giving of the cautionary instruction to be dispositive.

This is a very close question. On the one hand, the trial judge should never assume the role of an advocate. Such a course, especially given the stature of the trial judge in the eyes of the jury, can very easily prejudice the rights of the parties, particularly the rights of criminal defendants. See United States v. Lanham, supra, 416 F.2d at 1144. On the other hand, a federal trial judge may question the witnesses. See Kramer v. United States, supra, 408 F.2d at 841. In fact, the trial judge may call and question a witness not called by either party. See United States v. Lanham, supra, 416 F.2d at 1144, citing Gomila v. United States, 146 F.2d 372 (5th Cir. 1944). Judicial questioning of witnesses is frequently an attempt to clarify witnesses' testimony.

One of the chief roles of the trial judge is to see that there is no misunderstanding of a witness's testimony. The judge has a duty to comprehend what a witness says as much as it is his duty to see that the witness communicates with the jury in an intelligent manner. A trial judge can do this in a fair and unbiased way. His attempt to do so should not be a basis [for] error. Where the testimony is confusing or not altogether clear, the alleged "jeopardy" to one side caused by the clarification of a witness's statement is certainly outweighed by the desirability of factual understanding. The trial judge should strive toward verdicts of facts rather than verdicts of confusion.

Ray v. United States, supra, 367 F.2d at 261 (citations and footnote omitted).

We have thoroughly examined the entire record and are satisfied that the trial judge in questioning the witnesses was merely trying to clarify their testimony. Most of the trial judge's questions were directed to further explaining the mechanics of the rendezvous between the seller and buyer and the actual delivery. We are somewhat concerned with the trial judge's identification questions asked to Roger Burke and Boyce Cranford ( see Appendix A) and the employment questions asked of A.L. Scott ( see Appendix B). We conclude, however, that when reviewed in context these questions were neither improper nor prejudicial. The trial judge carefully refrained from making any comment on the evidence presented in the case and expressly instructed the jury that none of the trial judge's questions were intended to influence the jury in any way.

III. Granting a Continuance

Appellant next argues that the trial court abused its discretion in granting a continuance to the prosecution to develop additional circumstantial evidence on the issue of identification. The prosecution argues that the trial court did not abuse its discretion in granting a brief continuance in view of the surprisingly weak identification testimony by A.L. Scott, the chief prosecution witness. Further, the prosecution argues that the evidence introduced following the continuance was descriptive and essentially neutral in character, consisting of appellant's name, address and Social Security number. Cf. United States v. Dionisio, 410 U.S. 1, 93 S.Ct. 764, 35 L.Ed.2d 67 (1973) (voice exemplars compelled by grand jury); United States v. Mara, 410 U.S. 19, 93 S.Ct. 774, 35 L.Ed.2d 99 (1973) (handwriting exemplars); California v. Byers, 402 U.S. 424, 432, 91 S.Ct. 1535, 1539, 29 L.Ed.2d 9 (1971) (disclosure of name and address characterized as essentially neutral act); United States v. Turner, 565 F.2d 539 (8th Cir. 1977) (routine personal identification); United States v. Camacho, 506 F.2d 594 (9th Cir. 1974) (production by defendant of military identification card); United States v. Leal, 460 F.2d 385 (9th Cir. 1972) (identification of oneself), cert. denied, 409 U.S. 889, 93 S.Ct. 154, 34 L.Ed.2d 146 (1972). Of course, we note that this "essentially neutral" identification evidence tended to corroborate the prosecution's theory of the case.

We find no abuse of discretion. E. g., United States v. Little, 567 F.2d 346, 348 (8th Cir. 1977), cert. denied, 435 U.S. 969, 98 S.Ct. 1608, 56 L.Ed.2d 60 (1978). The trial court granted the continuance to enable the prosecution to present additional identification evidence in view of the surprisingly equivocal in-court identification by A.L. Scott, the chief prosecution witness. The additional evidence presented was essentially neutral in character. In addition, the length of the continuance was brief (from approximately 3:30 p. m. on the first day of trial to 11:40 a. m. the next day).

IV. Sufficiency of the Evidence

Appellant next argues that the trial court erred in refusing to grant his motion for judgment of acquittal. Related to this allegation of error is appellant's challenge that the verdict was against the great weight of the evidence. Appellant specifically argues there was insufficient evidence of interstate transportation and identification.

There is no doubt that the evidence presented was not overwhelming. Nonetheless, we have carefully reviewed the record and, considering the evidence in the light most favorable to the verdict, conclude that the evidence was sufficient to support the verdict. The prosecution presented evidence establishing that both cars were stolen (evidently car # 2 was stolen twice) in Michigan in September 1977. Shortly thereafter, both cars turned up in Arkansas in late September-early October 1977, allegedly transported there by appellant. "We have repeatedly held that possession in one state of property recently stolen in another state, if not satisfactorily explained, is a circumstance from which a jury may infer that the person knew the property to be stolen and caused it to be transported in interstate commerce." United States v. Brown, 535 F.2d 424, 430 (8th Cir. 1976), citing United States v. Harris, 528 F.2d 1327, 1331 (8th Cir. 1975). The record further shows that Roger Burke identified appellant as the individual who sold him car # 1. A.L. Scott was unable to positively identify appellant but testified about his acquaintance with appellant, their employer, Highway Dump Haulers, and their communications in arranging the sales of the cars. His testimony was corroborated in part by the W-4 withholding form.

V. Evidentiary Hearing

Appellant finally argues that the trial court erred in conducting an evidentiary hearing in the absence of appellant. As noted earlier, the trial court conducted an in-chambers proceeding about the additional identification evidence which the prosecution sought to introduce. Appellant argues that this proceeding was in fact a supplemental suppression hearing and thus a stage of the trial at which appellant should have been present. Fed.R.Crim.P. 43(a); United States v. Hurse, 477 F.2d 31, 33 (8th Cir.), cert. denied, 414 U.S. 908, 94 S.Ct. 245, 38 L.Ed.2d 146 (1973); cf. Jackson v. Hutto, 508 F.2d 890, 891 (8th Cir. 1975) (per curiam) ("Because a defendant's right to be present is, in the federal context, guaranteed by Fed.R.Crim.P. 43, the federal courts have, typically, not been called upon to determine the precise constitutional dimensions of this right. Nevertheless, there appears little doubt that a defendant's right to be present is constitutionally grounded in either the right to confrontation of the sixth amendment or the right to due process of the fifth and fourteenth amendments.") (citations omitted).

The prosecution notes that the record of the in-chambers proceeding does not indicate that appellant was not present. The prosecution argues that if appellant was in fact absent, defense counsel made no objection to appellant's absence and has thus waived any claim of error. See United States v. Jones, 542 F.2d 186, 213 (4th Cir.), cert. denied, 426 U.S. 922, 96 S.Ct. 2629, 49 L.Ed.2d 375 (1976). We agree. The record of the in-chambers proceeding indicates that defense counsel expressly objected to the trial judge's evidentiary rulings but not to appellant's absence from the proceeding (Tr. 165). See United States v. Brown, 571 F.2d 980, 987 (6th Cir. 1978); United States v. Sinclair, 438 F.2d 50, 52 (5th Cir. 1971), citing Deschenes v. United States, 224 F.2d 688, 693 (10th Cir. 1955).

In addition, we would not characterize the in-chambers proceeding at issue as a stage of the trial but as a conference upon a question of law, at which the defendant need not be present. Fed.R.Crim.P. 43(c)(3); e.g., Cox v. United States, 309 F.2d 614, 616 (8th Cir. 1962).

In any event, we can find no prejudice to appellant. The evidence introduced was "essentially neutral" identification information (name, address and Social Security number) and in part documentary (the W-4 withholding form containing similar identification information).

The general rule is that both the defendant and his counsel have the right to be present at all stages of the trial, from arraignment to verdict and discharge of the jury. However,

the existence of a right to be present depends upon a conclusion that absence could, under some set of circumstances, be harmful. Due process does not assure "the privilege of presence when presence would be useless, or the benefit but a shadow." Snyder v. Massachusetts, 1934, 291 U.S. 97, 106-07, 54 S.Ct. 330, 332, 78 L.Ed. 674 (Cardozo, J.)

Thus, a failure to comply with the automatic presence rule does not call for automatic reversal.

[E]ven improper exclusion of a defendant from a "critical" portion of the trial does not automatically require reversal, if in the particular case the defendant's absence was harmless beyond a reasonable doubt.

United States v. Walls, 577 F.2d 690, 698 (9th Cir. 1978) (other citations omitted), cert. denied, 439 U.S. 893, 99 S.Ct. 251, 58 L.Ed.2d 239 (1978), citing Polizzi v. United States, 550 F.2d 1133, 1138 (9th Cir. 1976) (other citations omitted); see also Faretta v. California, 422 U.S. 806, 819 n. 15, 95 S.Ct. 2525, 2533 n. 15, 45 L.Ed.2d 562 (1975) (that the right to be present granted by Fed.R.Crim.P. 43(a) is broader than that granted by the Constitution, which is only the "right to be present at all stages of the trial where his absence might frustrate the fairness of the proceedings . . . ."); United States v. Brown, supra, 571 F.2d at 986.

Accordingly, the judgment of the trial court is affirmed.

APPENDIX A

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APPENDIX B