For his first assignment of error, defendant contends his statutory and constitutional rights were violated because he was not arraigned in open court. Arraignment is mandatory unless waived in writing prior to the day for which arraignment is calendared in the manner provided by statute. G.S. 15A-945. An arraignment is a proceeding whereby a defendant is brought before a judge having jurisdiction to try the offense, so that the defendant may be formally apprised of the charges pending against him *63and directed to plead to them. G.S. 15A-941. Should the defendant fail to plead after the prosecutor has read the charges or otherwise fairly summarized them, the court must record the fact, and defendant must be tried as if he had entered a plea of not guilty. “Where there is no doubt that a defendant is fully aware of the charge against him, or is in no way prejudiced by the omission of formal arraignment, it is not reversible error for the trial court to fail to conduct a formal arraignment proceeding.” State v. Smith, 300 N.C. 71, 73, 265 S.E. 2d 164, 166 (1980).
Here the record is silent as to any arraignment. However, the judge in his charge to the jury said, “The defendant, by his plea of not guilty, has denied his guilt . . . .” The defendant was in court, his lawyer participated in the trial, and defendant called witnesses who testified in the defense of the defendant. Defendant in no way was prejudiced by the lack of formal arraignment and cannot now claim reversible error. State v. McCotter, 288 N.C. 227, 217 S.E. 2d 525 (1975). This assignment of error is overruled.
 Defendant claims the trial court erred in admitting his custodial statements because he was not warned of his Miranda rights and was seized without probable cause. Over defendant’s objections Officer Cline was permitted to testify to the jury that defendant had stated his height to be six feet, his weight 150 pounds, and that he had stated he was unemployed. Defendant contends the questions and answers were relevant to the identity of the defendant as being the intruder seen by Mr. Hollifield, and to defendant’s possible motive for having taken Mr. Hollifield’s billfold. We disagree.
A voir dire was heard to consider the admissibility of the challenged statement. Defendant on voir dire testified that he had not understood he was free to leave at the time he was being questioned at the sheriffs department by armed officers who were identified to him as detectives. The defendant, in fact, understood that he was coming to the courthouse, in addition to being directed by the officer to go there, to turn himself in on a probation violation. Officer Cline admitted defendant told him when he came to the sheriffs department “that he knew that there was a warrant or was going to be a warrant issued on him for a probation violation.”
*64At the conclusion of the voir dire, the trial court found as fact that the defendant was not under arrest, that he was not threatened, coerced, or intimidated in any manner, that no promises or threats were made, that defendant was free to leave at any time, and that it was not necessary or required that the Miranda warnings be given him as “Miranda warnings and waiver of counsel are required when, and only when, the defendant is being subjected to custodial interrogation.” State v. Sykes, 285 N.C. 202, 205, 203 S.E. 2d 849, 851 (1974). Defendant was not in custody at the time he answered the questions. Such personal data was nothing more than a general investigation of the offense. Defendant voluntarily came to the sheriffs office. He was free to leave. Therefore, the court concluded defendant’s statement as to date of birth, sex, race, age, height, weight, color of eyes, color of hair and nickname to be properly admissible.
The trial judge made findings of fact and rendered his conclusions thereon. If supported by competent evidence, the findings of fact are conclusive and binding on the appellate courts. State v. Thompson, 287 N.C. 303, 214 S.E. 2d 742 (1975). The record reveals sufficient evidence and testimony in support of the findings of fact. They in turn support the conclusions. We find no error in the ruling by the trial judge on this point.
 Defendant contends that the prosecutor’s statements made in his closing argument constituted prejudicial error. In the present case the defendant had presented to the jury evidence tending to show alibi. The prosecutor made statements suggesting that more evidence tending to show alibi would have been produced had certain witnesses testified. While it is improper for a lawyer in his argument to assert his opinion that a witness is lying, “he can argue to the jury that they should not believe a witness. . . .” State v. Noell, 284 N.C. 670, 696, 202 S.E. 2d 750, 767 (1974). In essence, the prosecutor’s comments constituted an argument to the jury that they should not believe defendant’s evidence of alibi, and therefore, the remarks represented a reasonable comment on the evidence.
We have examined defendant’s remaining assignments of error and find them without merit.
*65Chief Judge VAUGHN concurs.
Judge BECTON dissents.