Opinion by Judge GOULD; Partial Concurrence and Partial Dissent by Judge CALLAHAN.
GOULD, Circuit Judge:Tuyet Nguyen (“Nguyen”) appeals her jury conviction and sentence for conspiracy to transport stolen property in interstate commerce in violation of 18 U.S.C. § 2314, for two counts of the transportation of stolen property in interstate commerce in violation of 18 U.S.C. § 2314, for three counts of the introduction of misbranded medical devices into interstate commerce in violation of 21 U.S.C. § 352(a), and for conspiracy to commit money laundering in violation of 18 U.S.C. § 1956. We have jurisdiction under 28 U.S.C. § 1291. We affirm in part and reverse in part, and we remand for retrial and resentencing.
I
On July 13, 2005, a grand jury returned an indictment against Nguyen, her husband Phu Nguyen, their company Columbia Medical Systems, Inc. (“CMS”), and Sess Merke (“Merke”). The indictment alleged that Tuyet and Phu Nguyen conspired with Merke, Robert Davies (“Davies”), and others to steal and transport medical equipment from their former employer, ATL Philips Medical Systems (“Philips”). The indictment alleged that Nguyen had conspired to sell stolen ultrasound probes.1 The indictment alleged that the Nguyens resold these stolen probes through their company, CMS, after the probes were given new fake serial numbers. Merke and Davies withdrew from the conspiracy in 2000, but the government alleged that the conspiracy continued until 2003.
Davies, an unindicted co-conspirator, testified under a grant of immunity that Phu Nguyen, Appellant’s husband, asked him to steal probes and sell them to CMS. With the help of Davies, the conspiracy worked its fraud as follows: Davies would tell Philips that a customer had a broken probe that needed replacement, even though the probe was working. Philips would send the new probe to the customer, expecting that the customer would ship the broken probe back. Davies would give Phu Nguyen the customer’s old but still functioning probe, and Phu would transfer the functioning probe’s serial numbers onto one of the defective probes in the CMS stockroom. Then, Davies would send the defective probe to Philips. So, at Philips’s expense, Phu Nguyen and his company, CMS, would end up with functioning probes that were in effect stolen by fraud, and CMS would have given up only defective probes.
The fraudulent conspiracy was also furthered by the deception of others. Co-*672conspirator Merke stole Philips’s inventory from its stockrooms. At trial, Evalyn Thomas (“Thomas”), a Philips data entry clerk who worked for Merke, testified that Merke removed finished probes from the “Finished Goods” inventory without adequate explanation several times. Thomas explained that usually when an employee took material from the Finished Goods stockroom, they would fill out a Material Transfer Form. That form tracked where the material went. Thomas testified that it was unusual for someone in Merke’s position to be dealing directly with customers, and it was also odd that Merke personally pulled the stock and completed the entire form himself. According to Thomas, when the Material Transfer Form stated the employee was crediting the taken material to their “wash account,” the new material was being taken to replace some old, defective material. Therefore, a Material Transfer Form that took six parts frpm Finished Goods out of the stockroom and credited the “wash account” should also show the same number of parts going into the “Defective Material” stockroom. Thomas testified that this full accounting of material did not occur on several of Merke’s Material Transfer Forms. Instead, many parts “disappeared,” including forty-six ultrasound probes.
Another Philips employee, Dave West-rich (“Westrich”), testified that Nguyen asked him to load some of Philips’s proprietary software onto a hard drive for her. Westrich refused and told Nguyen not to call him again. The government contended that Nguyen must have obtained the software another way because Don Davis, a CMS customer, testified that in June 2001, Nguyen approached him with the suggestion that she would give him access to Philip’s software if he agreed to guarantee a certain level of business with CMS.
The prosecution introduced CMS business records to show that CMS sold more probes than it purchased for 1999 through 2003. FDA Agent Borden also explained that many Philips probes tied to CMS had false serial numbers. The police seized several probes with false serial numbers when executing a search warrant in December 2003. The testimony tied other probes with false serial numbers to CMS based on its invoices.
The prosecution also presented witnesses who said that having accurate serial numbers on ultrasound probes is important for FDA compliance, as well as for Philips’s inventory management. In a contract with CMS, one company included clauses emphasizing that CMS would only sell the company ultrasound components with original serial numbers. Also, a customer testified that he would return a product and refuse to pay for it if he discovered that it did not bear the original serial number.
The government alleged that the Nguyens paid for these stolen probes with cash to hide their origin. FDA Agent Mahoney testified that the Nguyens had made out several checks to cash with the notation “purchase probes Merke” and “purchase probes.” These checks were drawn from CMS accounts, and Nguyen signed and negotiated several checks.
The jury heard evidence of Nguyen’s statement in which she claimed that she and her husband did not buy any items from Merke, and that Merke had never delivered probes to her. Agent Borden also testified about statements that Merke had made during Merke’s interrogation. The government elicited information about that statement on direct examination, and Merke’s counsel elicited still more on cross-examination. Agent Borden testified that Merke had stated that he had sold stolen medical equipment to the Nguyens, *673and that he had received money from the Nguyens, though he refused to estimate how much money.
During closing arguments, Nguyen argued that the evidence did not establish whether she knew the probes were stolen or that the serial numbers had been changed.
On April 5, 2006, the jury found Nguyen guilty of conspiracy to transport stolen property in interstate commerce. The jury convicted her of transportation of stolen property for the shipment of probes on July 25, 2000, and August 15, 2000, but acquitted her of those charges for the shipments occurring on August 10, 2000, and April 3, 2002. The jury found her guilty of introducing misbranded medical devices into interstate commerce for the shipments of probes occurring on July 25, 2000, August 10, 2000, and August 15, 2000, but acquitted her of those charges pertaining to shipments on June 18, 2001, April 3, 2002, and December 3, 2002. The jury acquitted Nguyen of all five counts of holding for sale misbranded medical devices, Finally, the jury convicted her of conspiracy to commit money laundering.
The district court sentenced Nguyen to 48 months incarceration.
II
A.
We review claims of a violation of the Confrontation Clause de novo. United States v. Nielsen, 371 F.3d 574, 581 (9th Cir.2004).
The parties dispute whether Nguyen preserved this claim of error. Before trial, Nguyen made several motions in limine and objected to the use of a statement Merke made to Agent Borden, alleging that its admission would violate the Confrontation Clause. Nguyen objected to the admission of any portion of Merke’s statement that alluded to her both in the motion in limine and again at trial. The government argues that Nguyen should have objected to Merke’s use of his own statement when Merke’s counsel sent notice to all parties that Merke would admit his statements. Nguyen argues that she did not object because she understood Merke’s alert to mean that Merke would testify, curing any Confrontation Clause problem. Instead, Merke’s counsel elicited the statements for which Nguyen had a continuing objection. After opening statements at trial, the district court clarified that Nguyen did not need to make further objection on this issue and that the issue was preserved.2
We have held that “ ‘where the substance of an objection has been thoroughly explored and the trial court’s ruling was explicit and definitive, the issue is preserved for appeal.’ ” United States v. Varela-Rivera, 279 F.3d 1174, 1177 (9th Cir.2002) (quoting United States v. Palmer, 3 F.3d 300, 304 (9th Cir.1993)). As we have explained, Nguyen brought the Confrontation Clause issue to the district court’s attention twice, and the district court made a definitive ruling and then said she did not need to object further to preserve the issue. Accordingly, if there is Confronta*674tion Clause error, we must apply harmless error review. Nielsen, 371 F.3d at 581.
B
We turn to the issue of whether the Confrontation Clause was offended by introduction of the statement made by Merke as related by Agent Borden in her testimony. Agent Borden testified that while at first Merke had said that he received nothing more than lunch money, “he said a lot more things” including that he actually had received other money from the Nguyens, including money “that he had taken as a result of selling equipment to them,” but he would not specify the amount. She also testified that “equipment” included probes. The government had previously offered to redact the portion of Merke’s statement where he referenced accepting money from the Nguyens for stolen equipment to avoid any Confrontation Clause related errors, but Merke’s counsel elicited the testimony anyway.
Our Confrontation Clause analysis does not change because a co-defendant, as opposed to the prosecutor, elicited the hearsay statement. The Confrontation Clause gives the accused the right “to be confronted with witnesses against him.” U.S. Const. amend. VI; Crawford v. Washington, 541 U.S. 36, 43, 124 S.Ct. 1354, 158 L.Ed.2d 177 (2004). The fact that Nguyen’s co-counsel elicited the hearsay has no bearing on her right to confront her accusers. See also United States v. Mayfield, 189 F.3d 895, 901 (9th Cir.1999) (finding reversible error where a co-defendant’s counsel elicited hearsay statements in violation of the Confrontation Clause).
Only hearsay statements that are testimonial implicate the Confrontation Clause. Crawford, 541 U.S. at 68, 124 S.Ct. 1354. While the Court in Crawford did not comprehensively define testimonial statements, it stated that statements to a police officer during interrogations qualified. Id. at 52, 124 S.Ct. 1354. Merke made his statement during Agent Borden’s interrogation, and we conclude that it was testimonial.
This testimonial statement was hearsay. The government argues that Merke’s statement that he had sold the Nguyens scrap metal was admitted to show consciousness of guilt. The testimony, however, was broader and Agent Borden testified that Merke had sold the Nguyens medical equipment. This statement does not show Merke’s consciousness of guilt, nor is the statement “obviously false.” See, e.g., United States v. Trala, 386 F.3d 536, 544-45 (3rd Cir.2004) (holding in a case where the government sought to prove bank robbery, conflicting hearsay statements by a co-defendant regarding the origin of the money were admitted to show consciousness of guilt and were “obviously false”). Merke’s statement in which he said that he had received some money from the Nguyens but denied receiving half a million dollars was also not “obviously false.” See id. The government even acknowledged that this statement raised potential Confrontation Clause problems and offered to redact it.
The government argues that Merke’s statement was not inculpatory. But this is not controlling on the existence of error. Crawford does not require that a statement inculpate a defendant to trigger error under the Confrontation Clause. Simply, Confrontation Clause error occurs at admission of a testimonial statement without an opportunity to cross-examine. Crawford, 541 U.S. at 68-69, 124 S.Ct. 1354. If the statement is not inculpatory, that might be probative of the harmlessness of an error, but not of the existence of a Confrontation Clause error.
*675Because Merke’s statement was testimonial and admitted for its truth, we hold its admission at Nguyen’s trial was error.
C
The prosecution bears the burden of proving the error was harmless beyond a reasonable doubt. United States v. Gillam, 167 F.3d 1273, 1277 (9th Cir.1999) (“Once we find a [Confrontation Clause] error, the prosecution has the burden of showing that the error was harmless beyond a reasonable doubt.”); see also Chapman v. California, 386 U.S. 18, 24, 87 S.Ct. 824, 17 L.Ed.2d 705 (1967). “An assessment of harmlessness cannot include consideration of whether the witness’ testimony would have been unchanged, or the jury’s assessment unaltered, had there been confrontation; such an inquiry would obviously involve pure speculation, and harmlessness must therefore be determined on the basis of the remaining evidence.” Coy v. Iowa, 487 U.S. 1012, 1021-22, 108 S.Ct. 2798, 101 L.Ed.2d 857 (1988). “Whether an error is harmless depends on a variety of factors, including whether the testimony was cumulative, the presence or absence of corroborating or contradicting the testimony on material points, the extent of cross-examination, and of course, the overall strength of the prosecution’s case.” Mayfield, 189 F.3d at 906 (citation and internal quotations omitted).
The government argues that the error in admitting the hearsay statement was harmless.3 It contends that the evidence established that Merke had stolen probes from Philips, that both Nguyens had signed checks to Merke, some of which had “purchase probes Merke” on the memo line, that CMS had sold more probes than it had bought, that Phu Nguyen had solicited Davies to steal probes for CMS, that Tuyet Nguyen had solicited Westrich to steal Philips software for CMS, and that Tuyet Nguyen falsely denied doing any business with Merke. The statement that Merke received money from the Nguyens in exchange for medical equipment was the most persuasive evidence that tied Tuyet Nguyen to the stolen probes, and the only testimony that showed her knowledge that the probes were stolen.
We cannot say that the government carried its burden of establishing this error was harmless beyond a reasonable doubt. Specifically, the hearsay testimony supported the government’s case that Nguyen knew that the probes were stolen. Her knowledge was an element of her convictions for the transportation of stolen property and, therefore, necessary to her conspiracy convictions. Nguyen’s closing argument to the jury centered on her contention that she did not know the probes were stolen. While the jury could have concluded that she knew the probes were stolen absent the hearsay testimony, the government has not proven that the jury would have so concluded beyond a reasonable doubt. We reverse and remand Nguyen’s convictions for conspiracy to transport stolen property, conspiracy to commit money laundering, and the transportation of stolen property because Ngu*676yen was not able to cross-examine Merke about his statement. This Confrontation Clause error does not affect her convictions for introducing a misbranded medical device into interstate commerce.4
Ill
A.
We next address the conviction for felony misbranding of medical devices. The problem before us here is that the jury instruction that defined felony misbranding of medical devices did not include a materiality element. Nguyen did not object to the instruction and argues that we should apply plain error review.
The government to the contrary argues waiver and relies upon the invited error doctrine, which in an appropriate case allows us to decline to review instructions where a defendant invited the error and relinquished a known right. See United States v. Perez, 116 F.3d 840, 845 (9th Cir.1997). As the court in Perez stated, “[f]orfeited rights are reviewable for plain error, while waived rights are not.” Id. (citation omitted). Waiver occurs where a defendant “considered the controlling law, or omitted element, and, in spite of being aware of the applicable law, proposed or accepted a flawed instruction.” Id.
Nguyen proposed another instruction, Instruction 30, and the government contends that this instruction shows that she knew that materiality was an element of felony misbranding. Instruction 30, however, only states that any omission must be material, it does not say that an affirmative statement need be material. Therefore, it is not clear that Nguyen considered the controlling law and accepted the flawed instruction. We conclude that the waiver argument should be rejected and instead we accept Nguyen’s argument that we should review the jury instruction on felony misbranding of medical devices for plain error.
B
To prevail on plain error review, Nguyen must show (1) that the proceedings below involved error, (2) that the error is plain, and (3) that the error affected the substantial rights of the aggrieved party. See United States v. Olano, 507 U.S. 725, 732-35, 113 S.Ct. 1770, 123 L.Ed.2d 508 (1993). In addition, a defendant must also show that the error “ ‘seriously affect[s] the fairness, integrity or public reputation of judicial proceedings’ before we will exercise our discretion pursuant to Rule 52(b) to correct the plain error.” United States v. Alferahin, 433 F.3d 1148, 1154 (9th Cir.2006) (en banc) (citing Olano, 507 U.S. at 736, 113 S.Ct. 1770); see also United States v. Hai Waknine, 543 F.3d 546, 551 (2008).
Materiality indisputably is an element of felony misbranding of medical devices. United States v. Watkins, 278 F.3d 961, 969 (9th Cir.2002). It is thus somewhat surprising that the government’s proposed instructions did not include this element. The government concedes that Instruction 22 did not include that element *677but argues that this omission was cured by Instruction 30. That instruction stated:
If any article is alleged to be misbranded because the labeling or advertising is misleading, then in determining whether the labeling or advertising is misleading there shall be taken into account (among other things) not only representations made or suggested by statement, word, design, device, or any combination thereof, but also the extent to which the labeling or advertising fails to reveal facts material in the light of such representations or material with respect to consequences which may result from the use of the article to which the labeling or advertising relates under the conditions of use prescribed in the labeling or advertising thereof or under such conditions of use as are customary or usual.
This instruction does not cure the lack of materiality element. It states that the article could be misbranded because of a misstatement or a failure to state something that is material. Therefore, we hold the government’s argument is unavailing and that there was error. The instructions did not include the materiality element, this was an error and it is as simple as that.
C
It remains to be determined whether this error requires relief under the plain error standard. We believe that the first element of that standard is met. An error is plain when it is “clear” or “obvious” under the law. Olano, 507 U.S. at 734, 113 S.Ct. 1770. We have held that “a district court’s error is plain when its jury instructions fail to incorporate an element that has been clearly established by Ninth Circuit precedent.” Alferahin, 433 F.3d at 1157 (citation omitted). We hold that disregard of the materiality element for felony misbranding of medical devices is a plain error.
We turn next to the third element of the plain error standard, whether substantial rights are affected, and it is here that Nguyen’s appeal falters. “[T]he omission of an element from jury instructions does not always ‘affect’ a defendant’s substantial rights.” Id. (citing Neder v. United States, 527 U.S. 1, 15, 119 S.Ct. 1827, 144 L.Ed.2d 35 (1999)). Nguyen’s closing statement to the jury did not argue that the changed serial numbers were immaterial-it focused on the point that the numbers may have been changed by someone else and that Nguyen may have not known about it. Moreover, the government presented plenty of evidence to support a finding of materiality. Two customers testified that they would not buy ultrasound probes without original serial numbers. One of CMS’s customers included a clause in its contract stating that all probes would have original serial numbers. The testimony also demonstrated that the probes’ original serial numbers were critical for FDA compliance and in the event of a recall. Thus, there was overwhelming evidence of the materiality of the altered serial numbers and very little- evidence that these changes were unimportant.5
Because of the strong evidence on materiality and because Nguyen did not contest materiality of altered serial numbers in *678her presentations to the jury, we hold that this error did not affect Nguyen’s substantial rights.
IV
For the forgoing reasons, we conclude that Nguyen’s Confrontation Clause rights were violated and we REVERSE her convictions for conspiracy to transport stolen property, the transportation of stolen property, and conspiracy to commit money laundering. Her remaining convictions for felony misbranding of medical devices are AFFIRMED. We REMAND for retrial, if the government wishes to pursue the charges that we reverse, and for resentencing.
REVERSED IN PART, AFFIRMED IN PART, and REMANDED.
. An ultrasound probe is the part of the ultrasound machine that comes in contact with the patient’s body.
. The district court stated that Nguyen "[did not] have to object to preserve [the issue].” The government also argues that we should apply plain error because Nguyen did not move to sever Merke's trial from her own. The key question, however, is whether the issue was "brought to the court's attention.” Fed. R.Crim. Pro. 52(b) (plain error standard). Nguyen objected before and during trial, bringing her Confrontation Clause claim to the attention of both the district court and the government. A motion to sever was not necessary to avoid the plain error standard.
. The government also argues that the limiting instruction that these statements could only be used against Merke cured any error. In Bruton, the Court held that a case of the admission of a confession that implicates a co-defendant and .where the co-defendant cannot cross examine the confessor was a situation "in which the risk that the jury will not, or cannot, follow instructions is so great ... that the practical and human limitations of the jury system cannot be ignored.” Bruton v. United States, 391 U.S. 123, 135, 88 S.Ct. 1620, 20 L.Ed.2d 476 (1968). Therefore, we do not rely on the limiting instruction to cure the error.
. Merke’s statements do not affect the jury's verdict that Nguyen introduced misbranded medical devices into interstate commerce. For the jury to find that Nguyen committed this crime, it must find: that Nguyen (1) introduced (2) a medical device that is (3) materially adulterated or misbranded, and (4) that she acted with intent to defraud or mislead. 21 U.S.C. § 331(a); see also United States v. Watkins, 278 F.3d 961, 964 (9th Cir.2002). Nguyen did not need to know the probes had been stolen to commit this crime, only that their serial numbers had been altered. The hearsay statements do not discuss the probes’ serial numbers.
. Nguyen argues that there was conflicting and slim evidence regarding serial numbers' materiality. She states that there has never been a recall of ultrasound probes and that some evidence demonstrated that serial numbers were not unique to individual probes. She argues that serial numbers were for inventory control above anything else. But it is a sufficient answer that a recall could have occurred, and the serial numbers, whether unique or not, would have aided customers in identifying whether their probes were recalled.