announced the judgment of the Court.
Contrary to his pleas, a special court martial with officer members convicted Senior Airman Roy H. Ruiz of stealing several items from the Army and Air Force Exchange Service (AAFES) post exchange (PX) located at Fitzsimmons Garrison, Colorado.1 See Art. 121, Uniform Code of Military Justice, 10 USC § 921. His sentence included a bad-conduct discharge, confinement for 2 months, and reduction to the grade of E-1. This sentence was approved by the convening authority on September 24, 1997. The Court of Criminal Appeals affirmed the findings and sentence on December 21, 1998. 50 MJ 518.
This Court granted review of these issues:
I
WHETHER THE MILITARY JUDGE ERRED IN DENYING THE DEFENSE MOTION TO SUPPRESS STATEMENTS ALLEGEDLY MADE BY APPELLANT TO AAFES STORE DETECTIVES.
II
WHETHER IT WAS PLAIN ERROR FOR THE PROSECUTION TO CROSS-EXAMINE APPELLANT AND ARGUE, AND FOR THE MILITARY JUDGE TO PERMIT THE CROSS-EXAMINATION AND ARGUMENT, ABOUT THE FACT THAT APPELLANT DID NOT PROCLAIM HIS INNOCENCE WHEN HE WAS APPROACHED BY THE AAFES STORE DETECTIVES, IN VIOLATION OF APPELLANTS FIFTH AMENDMENT AND ARTICLE 31 RIGHTS.
Finding no prejudicial error, we affirm.
I. MOTION TO SUPPRESS STATEMENTS MADE TO AAFES STORE DETECTIVES.
As to appellants motion to suppress, the facts were summarized by the court below:
On 23 November 1996, Jean Rodarte, a civilian store detective for AAFES at the Fitzsimmons Garrison post exchange (PX), *140Colorado, observed the accused pick up a compact disc receiver in the electronics section of the PX and place it in his hand basket. He was wearing a large winter jacket despite relatively mild temperatures outside. Later, he went to the men’s clothing section and took an item into the dressing room. When he departed the dressing room, the accused took the receiver box back to the electronics section. The accused purchased a few items and then departed the store. On the street outside the PX, Ms. Rodarte and another store detective stopped the accused and asked him if he would accompany them back to the PX office. The accused agreed to do so. Once back in the office, the accused was invited to sit. Ms. Rodarte told the accused, “There seems to be some AAFES merchandise that hasn’t [sic] been paid for.” The accused said, ‘Yes,” took the receiver (without the box), a compact disc, and some razor blades from inside/under his coat and placed them on the table. He then said, ‘You got me.” Ms. Rodarte telephoned the Department of Defense (DoD) civilian police who were responsible for policing Fitzsimmons Garrison. While in the office, the store detectives asked the accused for his identification card, although Ms. Rodarte can not remember when in the sequence of events this occurred. When the DoD police arrived, Ms. Rodarte provided them with a statement describing this incident and then left the room. The empty box for the receiver was found on the shelf in the store.
Prior to entering his pleas, the accused moved to suppress the statements he made to Ms. Rodarte. The accused claimed that his statements were the product of an unlawful interrogation because Ms. Rodarte did not advise him of his rights under Article 31, UCMJ, 10 USC § 831. The accused did not assert that he was in custody, and therefore, should have been advised of his right to counsel. After conducting a hearing in which Ms. Rodarte was the only witness, the military judge denied the motion and admitted the accused’s statements and the merchandise he allegedly took from beneath his jacket. The military judge concluded that Ms. Rodarte’s statement was not an interrogation, so no Article 31(b) warnings were necessary, that the accused’s statements were spontaneous and voluntary, and that the evidence would have been inevitably discovered.
50 MJ at 519-20.
A military judge’s evidentiary rulings are generally reviewed under the abuse-of-discretion standard. However, a ruling that a statement was made voluntarily may present a question of law which this Court may review de novo. See United States v. Martinez, 38 MJ 82, 86 (1993). Likewise, whether an Article 31(b) warning is required may also require de novo review. United States v. Ravenel, 26 MJ 344, 352 (CMA 1988) (Cox, J., concurring in the result).
A person subject to the Uniform Code of Military Justice may not “interrogate” a suspect without first informing the suspect of the nature of the accusation, the right to remain silent, and that any statement made may later be used as evidence in a court-martial. Art. 31(b), UCMJ, 10 USC § 831(b). Subject to a few exceptions, any statement obtained in violation of this provision is inadmissible. Mil.R.Evid. 305(c) and 304(a), Manual for Courts-Martial, United States (1998 ed.). Moreover, the Manual for Court Martial requires that, under some circumstances, persons not subject to the Code provide warnings to a suspect.2
This Court has previously addressed the question whether an AAFES store detective must give a warning. United States v. Quillen, 27 MJ 312 (1988). There we held that an AAFES store detective “in a very real and substantial sense acted as an instrument of the military” and thus was subject to the warning requirement of Article 31(b). Id. at. 314. Despite the urging of the Government, we see no need to disturb or revisit that holding, even though in this case the military *141judge and the Court of Criminal Appeals have disagreed on whether the AAFES security personnel at Fitzsimmons were similarly instruments of the military and subject to the warning requirement of Article 31(b).
In denying the motion to suppress the accused’s statement to Ms. Rodarte, the military judge made several essential findings. Among other things the judge found
that Ms Rodarte and Ms Ray received specific training from AAFES which prohibits them from restraining or attempting to physically detain suspected shoplifters if they refuse to accompany them to the managers office or walk away from them. Similarly they are trained that they are not to ask questions or interrogate suspected shoplifters. They were however, trained to make the statement about unpaid merchandise as part of standard operating procedures. In making the statement, Ms Rodarte admitted that “we would hope to get a response,” but she didn’t expect anything in particular, because her experience in the past has been that a lot of times she doesn’t get a response, some suspects sit still and never respond.
On the basis of these findings, the judge distinguished Quillen, where “the scope and character of the cooperative efforts between BX store detectives and the base military police ... ‘merged into an indivisible entity.’ ” Furthermore, the judge found that “no interrogation” had been “conducted” within the meaning of Article 31(b).
Unlike the military judge, the Court of Criminal Appeals concluded that “[t]he facts of this case are not sufficiently different to distinguish it from Quillen.”3 Accordingly, that court held that the AAFES store detectives who detained Airman Ruiz were agents of the military who were subject to the Code and “required to advise him of his rights under Article 31(b) before interrogating him.” 50 MJ at 522.
We need not decide between the respective positions taken below to resolve the fact-specific issue of whether the Article 31(b) requirement applied to the AAFES security personnel in this case. Instead, we affirm because we join both the military judge and the Court of Criminal Appeals in holding that Ms. Rodarte did not “interrogate” the accused. We recognize, of course, that to conform with the purpose of Article 31, “interrogation” must be construed to include “any formal or informal questioning in which an incriminating response is sought or is a reasonable consequence of such questioning.” Mil.R.Evid. 305(b)(2). For example, asking a suspect to point out his clothing, his locker, or his automobile may constitute questioning and require a warning. See, e.g., United States v. Taylor, 5 USCMA 178, 17 CMR 178 (1954). Mil.R.Evid. 305(b)(2) is derived from Supreme Court precedents and was purposefully drafted in a broad fashion to thwart “attempts to circumvent warnings requirements through subtle conversations.” S. Saltzburg, L. Schinasi, and D. Schlueter, Military Rules of Evidence Manual 225 (4th ed.1997). Therefore, interrogation involves more than merely putting questions to an individual. Cf. Brewer v. Williams, 430 U.S. 387, 399, 97 S.Ct. 1232, 1240, 51 L.Ed.2d 424 (1977) (concluding that deliberately and designedly setting out to elicit information constituted interrogation).
*142Ruiz argues that Ms. Rodarte’s statement that “[tjhere seems to be some AAFES merchandise that has not been paid for” constituted an inteiTogation. In support of this contention, he points to the testimony of Ms. Rodai'te that the AAFES store detectives “would hope to get a response” when they make this statement. Appellant maintains that this statement constituted interrogation because an incriminating response either was sought or was a reasonable consequence of that statement.
However, interrogation does not include “words or actions ... normally attendant to arrest and custody.” Rhode Island, v. Innis, 446 U.S. 291, 301, 100 S.Ct. 1682, 1689, 64 L.Ed.2d 297 (1980). Accordingly, in United States v. Byers, 26 MJ 132 (1988), this Court noted that merely informing a person that he was suspected of using drugs would not mandate an Article 31 rights’ advisement. Id. at 135 n. 2.
In United States v. Powell, this Court concluded that initial statements made by a shoplifting suspect to AAFES store detectives had been “spontaneously made and not in response to interrogation.” However, this Court also ruled that later statements by the shoplifter were in response to interrogation. The former statements were made immediately after the suspect had been informed why he was being detained, 40 MJ 1, 3 (1994), while the later statements were made after a military policeman had arrived and after the suspect had been asked a number of further questions, id. at 2, 3.
Appellant tries to distinguish Powell on the ground that in Powell the shoplifting suspect initiated the conversation by asking the AAFES detectives why he was being detained. However, this is not a significant distinction because Ms. Rodarte’s statement — like the initial conversation in Powell — was merely informing appellant that he was suspected of not having paid for some merchandise. In Quillen, this Court noted that the questioning of the suspect went beyond asking him “to produce his receipt for the merchandise, a practice to which” this Court had “no objection on constitutional or codal grounds.” 27 MJ at 315. In this case, appellant treats as “interrogation” the mere statement that “[tjhere seems to be some AAFES merchandise that has not been paid for.” In context, however, this statement is not functionally different from asking the suspect to provide a receipt for the stolen merchandise or informing him of the potential charges against him.
Accordingly, we agree with the lower court’s holding “that Ms. Rodarte did not inteiTOgate the accused,” but instead “did no more than advise the accused why he was stopped and why she asked him to accompany her back to the office.” 50 MJ at 522. Because Ms. Rodarte’s statements and actions constituted words and actions normally attendant to the detention process for suspected shoplifters, the accused’s statements were voluntary and admissible under the Military Rules of Evidence and the precedents of this Court and the Supreme Court.
II. THE TRIAL COUNSEL’S COMMENTS ON THE ACCUSED’S SILENCE.
Sergeant Ruiz took the stand to testify in his own defense. His testimony, which was in substantial conflict with that of the prosecution witnesses, was summarized by the court below in this manner:
On direct examination, he testified that he looked at the CD player, put it back on the shelf, bought a few minor items, and then, without exiting the store, decided to go back and purchase the CD player and razor blades. He insisted that he was taking the CD player to the layaway counter when Ms. Rodarte stopped him, inside the PX. He claimed that the CD player was under his arm, not his jacket, and that it was still in its box when he handed it over to the store detectives. He claimed that the CD player was taken out of the box when the store detectives and Officer Segrest were searching for the accused’s identification card.
During cross-examination, the accused testified that he did not go to the dressing room and that he actually exited the exchange, but was still inside the building, in the foyer where concessionaires sell merchandise, when Ms. Rodarte stopped him. He also disputed Ms. Rodarte’s version of *143what happened in the manager’s office. The accused insisted that when they arrived at the manager’s office, he asked, “Is there a problem? I can pay for these items,” to which one of the detectives answered, “It’s too late.” To test the credibility of this statement, the trial counsel asked the accused if he had ever said, “Too late for what?” The accused claimed to have instead asked, “What’s going on?” to which the detective did not reply. Trial counsel then asked the accused if he had protested his innocence. The accused testified that he did not because they might use it against him. The trial counsel continued to probe how little sense that made in light of his other questions to the detectives. Trial counsel also questioned why the accused did not proclaim his innocence to Officer Segrest when he arrived on the scene. The accused replied that he knew Officer Segrest did not have the authority to release him, so it would have been a wasted effort.
During his closing arguments on findings, the trial counsel highlighted the differences between the testimonies of the prosecution witnesses and of the accused. He also commented on the unreasonableness of the accused’s version of what occurred in the manager’s office. The trial counsel repeated this theme during his rebuttal argument.
50 MJ at 523.
Despite the failure of his counsel to object at trial, appellant now asserts that he should not have been cross-examined about his failure to proclaim his innocence and that the prosecutor should not have argued any inferences therefrom.
Usually any objection to questions asked on cross-examination must be made at the time they are asked. Also, failure to make timely objection to matters raised in argument will waive any issue on appeal with respect thereto in the absence of plain error. See United States v. Ramos, 42 MJ 392, 397 (1995). To show plain error, an appellant must establish an error which “must not only be both obvious and substantial, it must also have ‘had an unfair prejudicial impact on the jury’s deliberations.’ ” United States v. Fisher, 21 MJ 327, 328 (CMA 1986) (quoting United States v. Young, 470 U.S. 1, 16-17 n. 14,105 S.Ct. 1038, 1047, 84 L.Ed.2d 1 (1985)); see also United States v. Powell, 49 MJ 460 (1998); United States v. Riley, 47 MJ 276 (1997). This Court may exercise its discretion to reverse on a forfeited error only if the error materially prejudices the substantial rights of appellant, see Powell, 49 MJ at 465, or the error seriously affects the fairness, integrity, or public reputation of judicial proceedings, see Johnson v. United States, 520 U.S. 461, 467, 117 S.Ct. 1544, 1549, 137 L.Ed.2d 718 (1997). The plain-error doctrine “is to be used sparingly, solely in those circumstances in which a miscarriage of justice would otherwise result.” United States v. Frady, 456 U.S. 152, 163 n. 14, 102 S.Ct. 1584, 1592 n. 14, 71 L.Ed.2d 816 (1982).
Certainly this is not a case where plain error was committed. Indeed, we doubt that there was any error whatsoever. Of course, as Sergeant Ruiz contends, “A person’s failure to deny an accusation of wrongdoing concerning an offense for which at the time of the alleged failure the person was under official investigation ... does not support an inference of an admission of the truth of the accusation.” Mil.R.Evid. 304(h)(3); see also United States v. Cook, 48 MJ 236 (1998) (holding military judge erred by admitting, over objection of the accused, evidence of an accused’s silence in response to a friend’s question as to whether he had committed rape).
Here, however, trial counsel “was not commenting on the accused’s silence.” As the court below noted, “the prosecutor was attacking the accused’s version of the events in the manager’s office,” which portrayed him “as an innocent man ... wrongly accused ... by the lying AAFES store detective.” In his testimony, appellant had “contradicted Ms. Rodarte’s version of’ the events and conversations at the store. Trial counsel “had a duty to ... point out the inconsistencies and” unbelievable nature of appellant’s story. Like the court below, we also “suspect that the defense counsel and the experienced military judge did not intervene because they *144recognized the prosecutor’s actions for what they were — proper cross-examination.” 50 MJ at 525. Trial counsel was not focusing on appellant’s silence but instead was attacking the credibility of what appellant claimed he did say. This was perfectly appropriate cross-examination and argument.
Conclusion
The decision of the United States Air Force Court of Criminal Appeals is affirmed.
. Until recently this was the location of Fitzsimmons Army Hospital.
. On the other hand, we have held that under some circumstances a person subject to the Code — for example, an undercover agent — is not within the scope of the warning requirement in Article 31(b). See, e.g., United States v. Gibson, 3 USCMA 746, 14 CMR 164 (1954).
. As the Court of Criminal Appeals noted, "Since Quillen, it appears that AAFES has attempted to change the way in which store detectives operate.” 50 MJ 518, 521 (1998) (observing that the detective in question “testified that she doesn’t work for any military establishment,” or "in conjunction with any military law enforcement agency[,]” nor has she received any training from the military). However, the court below, after reviewing the applicable regulations, concluded that "[Ijittle, if anything has changed, since the Court of Military Appeals found that AAFES ‘was under the control of military authorities.’ ” Id. (quoting United States v. Quillen, 27 MJ 312, 314 (1988)). AAFES remains "a joint command of the Army and Air Force. Air Force Regulation (AFR) 147-7. Army and Air Force Exchange Service General Policies, ¶ 1-7a (17 June 1988). Installation commanders” are still under the obligation to "ensure that 'incidents of criminality’ at exchanges are reported ... to the appropriate military investigative organization^] [i]d. at ¶ 2-6a(8)[,]” and commanders are still "responsible for revoking or suspending exchange privileges of those who steal AAFES merchandise. AFR 147-14, Army and Air Force Exchange Service Operating Policies, 112-15 (15 Jan. 93).” 50 MJ at 521.