The opinion of the court was delivered by
ROSEN, J.:Donnie Ventris petitioned this court to review the Court of Appeals’ decision affirming his convictions for aggravated robbery and aggravated burglary. Ventris asserts that the district court improperly admitted impeachment testimony from a jailhouse informant who had been surreptitiously planted in his jail cell by the State; that the district court improperly admitted evidence in violation of K.S.A. 60-455; and that his sentence should be reversed because the determination of his criminal history was not proven to a juiy beyond a reasonable doubt.
The following facts are taken from the Court of Appeals’ decision:
“Sometime in the last part of 2003, Ventris met and began living with Rhonda Theel in a romantic relationship. At some point, Theel learned from another friend, Kim Eytcheson, about the victim in this case, Ernest Hicks. She heard that Hicks was abusing the children of his live-in girlfriend, Helen Cargile. She also *597heard that Hicks was wealthy and carried $500 to $600 on his person. Eytcheson was also a friend of Cargile.
“On January 6, 2004, and into the early morning hours of January 7, 2004, Theel and Ventris were using methamphetamine and marijuana at their home. Neither had slept for a couple of days. At approximately 6 a.m., Theel suggested to Ventris that they go to Hicks’ residence so she could talk to Hicks about die alleged child abuse. Theel called Eytcheson to find out when Cargile’s children left for school. Theel also called another friend, Martha Denton, and asked Den-ton to meet her and Ventris at Tump Station Road.’ Theel wanted Denton to give her and Ventris a ride to Hicks’ residence, because she thought it would be best not to drive Ventris’ car all the way to Hicks’ house.
“Denton did not know why Theel wanted to meet her at Pump Station Road. Nevertheless, she proceeded to the meeting place with her boyfriend, Keith Holt. By this time, Ventris and Theel had arrived at the meeting place in Ventris’ truck and began watching Hicks’ residence, waiting for Cargile to leave with her children. When Denton and Holt arrived, Theel asked Holt to take her and Ventris to Hicks’ residence and told Denton to take Ventris’ truck with her. Denton and Holt complied.
“Theel gave Holt directions to Hicks’ residence. She also told him that she and Ventris were going there so a guy could show them a dog. As they arrived at Hicks’ residence, Theel noted that Hicks’ truck was in the driveway and told Holt to drive past the house, turn around, head back towards the residence, and turn into the driveway next to Hicks’ truck. Ventris ‘never said a word.’
“After Holt pulled into the driveway, Theel exited the vehicle and told Ventris to wait while she went to the door and knocked. Theel had also told Holt he could leave, because the guy living at the house was supposed to give her and Ventris a ride back. According to Holt’s trial testimony, Ventris waited behind a black pickup while Theel knocked on the door. As Holt pulled out of the driveway, he saw Ventris pull a ski mask down over his face, but Holt could not tell whether the ski mask left Ventris’ face open or covered everything but his eyes. The outside temperature was 5 to 10 degrees that morning.
“While Theel and Ventris were inside Hicks’ residence, one or both of them shot and killed Hicks with a .38 revolver, took his wallet containing approximately $300, and a cell phone. Theel drove herself and Ventris in Hicks’ truck to a secluded spot in Oklahoma where she sprayed the truck with cleaner to get rid of any fingerprints. The two of them then walked to a convenience store. On the way, Theel tried unsuccessfully to disassemble the murder weapon. One of them disposed of the gun in a culvert.
“At the convenience store, Theel called Denton and asked her for a ride home. Denton and Holt eventually picked Theel and Ventris up at the store and took them back to their home in Kansas. Sometime later, Denton and Holt contacted the police after developing a suspicion that Theel and Ventris had something to do with Hicks’ murder. Police arrested both Theel and Ventris and charged them each with several crimes.
*598“Theel entered into a plea bargain in exchange for her testimony against Ventris. Specifically, she pled guilty to aggravated robbery and aiding a felon. The State tried Ventris before a jury on charges of felony murder, aggravated robbery, aggravated burglary, felony theft, and misdemeanor theft. Theel, Ventris, and a former cellmate of Ventris’ all testified at trial. Both Ventris and Theel denied taking a gun to Hicks’ residence, and they both claimed the reason for going to the residence was for Theel to talk to Hicks about the alleged child abuse. However, each related a different version of the events that occurred after arriving at Hicks’ residence.
“Highly summarized, Theel testified as follows. As she was waiting for Hicks to come to the door, she saw a frightened look on Hicks’ face and then Ventris quickly passed her and entered the house. She then entered and almost immediately saw Hicks on the floor and Ventris standing over him. She heard them arguing. She then saw that Ventris had a .38 revolver and heard him ask Hicks about money. She attempted to stop the two from arguing by dousing them with a cleaner she retrieved from the kitchen and by also hitting Hicks with a stick. Hicks produced a wallet and Ventris said, ‘All this for 40 or 50 dollars?’ The two men walked to the bedroom after Hicks said he had more money there. Theel then heard two shots and saw Ventris come out of the bedroom. She claimed Ventris said, T have to shoot him again,’ to which she responded, ‘Okay.’ According to her testimony, she then left the house and at some point heard a third shot. Ventris then came out of the house and threw Hicks’ truck keys to her. She used the keys to gain access to Hicks’ truck and drove herself and Ventris away from tire scene.
“Ventris, as one might anticipate, offered a different version as follows. He testified that he only went with Theel on the day in question to ‘shut her up’ since she had been talking for days about Hicks committing child abuse. He denied hearing about Hicks and his money. He also denied taking a gun with him and did not know if Theel had one. He denied knowing that Theel had called Denton to arrange a ride, but he admitted going to the meeting place where they met Denton and Holt. There he and Theel entered Holt’s car and traveled to Hicks’ house. Once there, Hicks became agitated with Theel over her accusations of child abuse. A scuffle ensued between himself and Hicks, and Theel threw a liquid in Hicks’ face and hit him with a stick. Theel then pulled out a gun and asked Hicks for his wallet. Ventris asked her what she was doing, and she replied that he should mind his own business. Hicks said his wallet was in the bedroom, and she told him to go get it. Theel and Hicks went into the bedroom, and Theel shot him. Ventris started to leave and then heard two more shots. He denied taking anything with him when he left. He got into the truck with Theel only after she said she would take him to his truck. Nevertheless, they continued on to a gas station where he purchased gas with money Theel gave him.
“As stated earlier, the State also offered at trial the testimony of Johnnie Doser, Ventris’ former cellmate, as a rebuttal witness. Prior to trial, the State recruited Doser to share a cell with Ventris and to ‘keep [his] ear open and listen’ for *599incriminating statements. According to Doser, Ventris told him that he and his girlfriend ‘went to rob somebody and that it went sour.’ Ventris allegedly said he shot a guy in the head and chest and took his keys, his wallet, about $350, and a vehicle. In exchange for Doser’s testimony, the State released him from probation. Ventris objected to the testimony, claiming the State had obtained the statements in violation of his Sixth Amendment right to counsel. The State conceded the Sixth Amendment violation but argued the testimony could be used for impeachment purposes. The trial court allowed Doser to testify.
“Prior to closing arguments, the trial court instructed the jury to ‘consider with caution’ the testimony of both Doser and Theel. The jury deliberated for approximately 2 hours and acquitted Ventris of felony murder and misdemeanor theft. However, the jury found him guilty of aggravated burglary and aggravated robbery. The court had previously dismissed the felony theft charge due to a lack of evidence. Later, the court sentenced Ventris to 247 months for aggravated robbery and 34 months for aggravated burglary.” Slip op at 3-8, State v. Ventris, No. 94,002, unpublished opinion filed September 15, 2006.
The Court of Appeals affirmed Ventris’ convictions and sentences. Ventris, slip op. at 17. Ventris petitioned this court to review the Court of Appeals’ decision, and we granted his petition.
For his first issue, Ventris claims that the district court erroneously admitted testimony from his former cellmate, who had been surreptitiously placed in Ventris’ jail cell to obtain incriminating statements. Ventris claims that his former cellmate’s testimony violated his Sixth Amendment right to counsel.
When an appellate court reviews the district court’s decision regarding the suppression of evidence, it gives deference to the trial court’s factual findings but applies a de novo standard to the ultimate legal determination of whether the evidence should have been suppressed. State v. Coleman, 275 Kan. 796, 805, 69 P.3d 1097 (2003).
The State concedes that it violated Ventris’ Sixth Amendment right to counsel when it surreptitiously planted Doser in Ventris’ jail cell as a human listening device. Nevertheless, the State argues that the evidence is only precluded from its case-in-chief. The State asserts that it can use the illegally obtained statements in rebuttal to impeach Ventris’ testimony.
To support its argument, the State relies on Harris v. New York, 401 U.S. 222, 28 L. Ed. 2d 1, 91 S. Ct. 643 (1971). In Harris, the defendant was charged with selling heroin to an undercover police *600officer. After Harris was arrested, he made several incriminating statements to the officers without the benefit of proper Miranda warnings. Harris testified in his defense, stating that he had sold baking powder to the officers as part of a scheme to defraud drug purchasers. On cross-examination, the State attempted to impeach Harris’ testimony by inquiring about several contradictoiy statements Harris had made after his arrest. The State conceded that the statements were inadmissible in its case-in-chief because they were obtained without Miranda warnings but asserted that the statements were admissible for impeachment. 401 U.S. at 223-24.
In a five-to-four decision, the United States Supreme Court agreed with the State. Harris, 401 U.S. at 224-25. The Harris Court relied on Walder v. United States, 347 U.S. 62, 98 L. Ed. 503, 74 S. Ct. 354 (1954), which allowed the admission of illegally obtained physical evidence to impeach the defendant even though the evidence was not admissible in the government’s case-in-chief. Harris, 401 U.S. at 224-26. Stating that “[t]he shield provided by Miranda cannot be perverted into a license to use perjury by way of a defense, free from risk of confrontation with prior inconsistent utterances,” the Harris Court concluded that the Court’s truth-seeking function outweighed the protection against self-incrimination afforded by Miranda. 401 U.S. at 226.
In Oregon v. Hass, 420 U.S. 714, 43 L. Ed. 2d 570, 95 S. Ct. 1215 (1975), the United States Supreme Court extended the holding in Harris to include statements made in violation of a defendant’s Fifth Amendment right to counsel. Hass was arrested for stealing bicycles. The police advised Hass of his Miranda warnings at the time of his arrest. Hass requested to speak with his attorney and was advised that he could call an attorney when they arrived at the police office. On the way there, Hass pointed out the houses where the bicycles had been stolen and the location of a stolen bicycle. At trial, Hass testified that he did not know his friends were going to steal bicycles or from where the bicycles had been stolen. To impeach this testimony, the State admitted the statements Hass had made after his arrest. 420 U.S. at 715-17. The Hass Court affirmed the use of the defendant’s statements to im*601peach his testimony, finding no evidence or suggestion that the statements were involuntary or coerced. 420 U.S. at 722.
This court has applied the United States Supreme Court’s analysis in Harris and Hass. In State v. Osbey, 213 Kan. 564, 573-74, 517 P.2d 141 (1973), the defendant claimed that the trial court erroneously admitted portions of his confession because there had been no hearing outside the presence of the juxy to determine the voluntariness of the confession. Relying on Harris, the State claimed that the confession was properly admitted as rebuttal evidence to impeach the defendant. The Osbey court agreed with the State, concluding that the statements were properly admitted as rebuttal evidence even though they were not admissible in the State’s case-in-chief. 213 Kan. at 574. See also State v. Andrews, 218 Kan. 156, 159, 542 P.2d 325 (1975) (same issue).
The facts in State v. Boone, 220 Kan. 758, 768-69, 556 P.2d 864 (1976), are similar to those in Hass. Boone requested to speak with an attorney after he was arrested and the officers had given him Miranda warnings. However, before Boone had an opportunity to talk to an attorney, the officers obtained a statement from Boone regarding his whereabouts prior to his arrest. At trial, Boone testified differently about his whereabouts before his arrest, and the State offered the officer’s testimony to impeach him. The Boone Court relied on Harris and Hass in concluding that the evidence was properly admitted to impeach Boone, even though it was inadmissible in the State’s case-in-chief. Boone, 220 Kan. at 768-69. See also State v. Graham, 244 Kan. 194, 203-04, 768 P.2d 259 (1989) (allowing statements made without Miranda warnings to be used to impeach the defendant’s testimony); State v. Greene, 214 Kan. 78, 82, 519 P.2d 651 (1974) (admitting statements made with improper Miranda warnings to be used for impeachment); State v. Robinson, 4 Kan. App. 2d 428, 433, 608 P.2d 1014 (1980) (assuming that the defendant did not properly and effectively waive his Miranda rights but allowing the State to use the statements to impeach the defendant); State v. Stoops, 4 Kan. App. 2d 130, 134-35, 603 P.2d 221 (1979) (affirming the admission of statements made to police after the defendant invoked his right to counsel to impeach the defendant). Cf. State v. Roberts, 223 Kan. 49, 57-58, *602574 P.2d 164 (1977) (distinguishing Harris and Hass and precluding the admission of involuntary statements to impeach the defendant).
In keeping with its decisions in Harris and Hass, the United States Supreme Court extended the Fifth Amendment analysis to a Sixth Amendment issue in Michigan v. Harvey, 494 U.S. 344, 350-51, 108 L. Ed. 2d 293, 110 S. Ct. 1176 (1990). Two months after Harvey had been arraigned on two counts of rape, he told a police officer that he would like to make another statement but did not know if he should talk to his attorney. The officer told Harvey that he did not need to speak with his attorney because his attorney would get a copy of the statement anyway. After signing portions of a constitutional rights waiver indicating that he understood his right to remain silent and have an attorney present during the questioning, Harvey made statements that were inconsistent with his later trial testimony. The State conceded that Harveys statements were not admissible during its case-in-chief, but argued that under Harris, the statements were admissible to impeach Harvey. 494 U.S. at 346-47.
In another five-to-four decision, the Harvey Court agreed with the State but remanded the matter for factfinding to determine whether Harvey had knowingly and voluntarily waived his Sixth Amendment right to counsel. 494 U.S. at 354. The Harvey Court noted the prophylactic rule from Michigan v. Jackson, 475 U.S. 625, 89 L. Ed. 2d 631, 106 S. Ct. 1404 (1986), which requires the exclusion of any statements made to police after the Sixth Amendment right to counsel has attached if the police initiated the conversation. Reasoning that the Jackson prophylactic rule was analogous to the Miranda prophylactic rule, the Harvey Court extended its holding in Harris to apply to Sixth Amendment violations. 494 U.S. at 349, 351. The Harvey Court stated that the “ ‘search for the truth in a criminal case’ outweighs the ‘speculative possibility that exclusion of evidence might deter future violations of rules not compelled directly by the Constitution in the first place,” 494 U.S. at 351-52.
The dissenting justices in Harvey refused to reduce the Sixth Amendment right to counsel to the status of a prophylactic rule, stating:
*603“The exclusion of statements made by a represented and indicted defendant outside the presence of counsel follows not as a remedy for a violation that has preceded trial but as a necessary incident of the constitutional right itself. ‘[T]he Sixth Amendment right to counsel exists, and is needed, in order to protect the fundamental right to a fair trial.’ Strickland v. Washington, 466 U.S. 668, 684, [80 L. Ed. 2d 674, 104 S. Ct. 2052 (1984)]. It is not implicated, as a general matter, in the absence of some effect of the challenged conduct on the trial process itself. [Citations omitted.] It is thus the use of the evidence for trial, not the method of its collection prior to trial, that is the gravamen of the Sixth Amendment claim.” 494 U.S. at 362-63.
In this case, the State’s reliance on Harris and its progeny does not reconcile the factual distinction between those cases and this case. In Harris, Hass, and Harvey, the defendant dealt directly with law enforcement officers. In contrast, the statements at issue in this case were made to a jailhouse informant who was surreptitiously acting as an agent of the State. We believe this factual distinction is significant.
The United States Supreme Court addressed the impact of jailhouse informants on the Sixth Amendment right to counsel in United States v. Henry, 447 U.S. 264, 65 L. Ed. 2d 115, 100 S. Ct. 2183 (1980). In Henry, government agents sought assistance from an jailhouse informant who had provided confidential information to the government for over a year. The government agents aslced the jailhouse informant to be “alert to any statements” made by Henry and other federal prisoners. 447 U.S. at 266. Henry confided in the jailhouse informant about his involvement in a bank robbery and sought the informant’s assistance in breaking out of jail. The jailhouse informant testified against Henry at his trial.
The Henry Court held that the admission of the jailhouse informant’s testimony violated Hemy’s Sixth Amendment right to counsel. 447 U.S. at 274. The Henry Court relied on Massiah v. United States, 377 U.S. 201, 12 L. Ed. 2d 246, 84 S. Ct. 1199 (1964), which held that the government cannot use a defendant’s incriminating statements when the statements are obtained by a surreptitious informant working as an agent for the government. Noting that the “concept of a knowing and voluntary waiver of Sixth Amendment rights does not apply in the context of communications with an undisclosed undercover informant acting for the Gov*604emment,” the Henry Court concluded that Henry’s statements “should not have been admitted at trial.” (Emphasis added.) 447 U.S. at 273-74. The Henry Court distinguished between Fourth and Fifth Amendment cases, stating that “those cases are not relevant to the inquiry under the Sixth Amendment here—whether the Government has interfered with the right to counsel of the accused by ‘deliberately ehciting’ incriminating statements.” 447 U.S. at 272. Unlike the Court’s analysis in Harris, Hass, and Harvey, the Henry Court did not consider whether the government violated a prophylactic rule or a constitutional right.
Neither this court nor the United States Supreme Court has previously addressed the issue presented by the facts of this case. Although the Harvey Court addressed a related issue, it specifically left open the question presented by the facts in this case, stating,' “we need not consider the admissibility for impeachment purposes of a voluntary statement obtained in the absence of a knowing and voluntary waiver of the right to counsel.” 494 U.S. at 354. However, a few other jurisdictions have squarely addressed the issue.
In United States v. McManaman, 606 F.2d 919 (10th Cir. 1979), the Tenth Circuit allowed the admission of statements the defendant made to an undercover informant for the purpose of impeaching the defendant’s testimony. Deciding the issue without the benefit of the Henry decision, the McManaman court refused to extend the Massiah rule, which precludes the admission of evidence obtained by an undercover informant while the defendant is represented by counsel. Instead, the McManaman court relied on the reasoning in Walder, stating that a defendant is not free to make a sweeping denial of the charges by “possibly peijurious testimony, in reliance on the Government’s inability to challenge his credibility because its rebuttal evidence was illegally secured.” 606 F.2d at 925.
Likewise, in United States v. Langer, 41 M.J. 780 (A.F. Ct. Crim. App. 1995), the United States Air Force Court of Criminal Appeals allowed the admission of the defendant’s statements to an undercover informant to impeach the defendant’s testimony. Relying on Harvey, the Langer court stated:
*605“We see no significant distinction between a Sixth Amendment violation committed in a station house, by police officers who have identified themselves to a suspect, and a covert one committed by an undercover agent. In each instance, society demands that the prosecution pay a price so that future violations maybe deterred. That price is exclusion of the tainted evidence from the prosecution case-in-chief. However, society should not be made to suffer a Sixth Amendment violation as a license for an accused to commit perjury without fear of contradiction. Such a cost is too high.” 41 M.J. at 784.
In United, States v. Martin, 974 F. Supp. 677 (C.D. Ill. 1997), a federal district court in Illinois ruled that the Government could use the defendant’s statements to an undercover agent to impeach the defendant’s testimony. The Martin court concluded that the defendant’s statements to the undercover agent were voluntary but that he had not made a knowing and voluntary waiver of his right to counsel. Nevertheless, the Martin court reasoned that barring the defendant’s statements “would diminish the Court’s truth-seeking purpose in a criminal trial and would give too little weight to antipeijury considerations.” 974 F. Supp. at 684.
In contrast, the Supreme Court of Maine held that the State could not use surreptitiously recorded statements obtained in violation of the defendant’s right to counsel to impeach the defendant’s testimony. State of Maine v. York, 705 A.2d 692 (Me. 1997). Concluding that offering the evidence amounted to a constitutional violation rather than the violation of a prophylactic rule because the defendant did not waive his right to counsel, the York court distinguished Harvey and refused to admit the evidence for any purpose. 705 A.2d at 695.
From these cases, we have discerned two analytical approaches for resolving the issue. The first approach focuses on the court’s truth-seeking function by denying the defendant an opportunity to commit perjury without contradiction. This approach ignores Henry and tire requirement that defendants make a knowing and voluntary waiver of their Sixth Amendment right to counsel. The second approach requires a knowing and voluntary waiver of the Sixth Amendment right to counsel. The knowing and voluntary waiver is not dependent upon whether the defendant will have an opportunity to commit perjury.
*606The Court of Appeals followed the first approach, focusing on the court’s truth-seeking function and preventing perjury. While this approach is supported by McManaman, Longer, and Martin, it fails to harmonize the United States Supreme Court’s decisions in Henry and Harvey. The Harvey Court refused to address the admission of statements made without a knowing and voluntary waiver of the Sixth Amendment right to counsel. The Henry Court concluded that a defendant cannot knowingly and voluntarily waive his Sixth Amendment rights if he or she is dealing with an undercover informant. Considering Harvey in conjunction with Henry leads us to conclude that the second approach applied by the York court is more constitutionally sound.
A criminal prosecution commences when a complaint is filed and a warrant issued. The defendant’s Sixth Amendment right to counsel attaches at that point. State v. McCorgary 218 Kan. 358, 361, 543 P.2d 952 (1975) cert, denied 429 U.S. 867 (1976). Once a criminal prosecution has commenced, the defendant’s statements made to an undercover informant surreptitiously acting as an agent for the State are not admissible at trial for any reason, including the impeachment of the defendant’s testimony. Cf. State v. Pennington 276 Kan. 841, 846, 80 P.3d 44 (2003) (allowing statements from an undercover jailhouse informant acting as an agent for the State because the defendant had not been charged with the crime at issue). Although trial judges are called upon to determine the admissibility of evidence to effectuate the courts’ truth-seeking function, there is nothing in our federal or state constitutions that requires us to malee truth-seeking the overriding principle that trumps our constitutionally protected rights. By following the first approach, the Court of Appeals primarily focused on admissibility of rebuttal evidence rather than the impact of such a glaring violation of a constitutional right.
Without a knowing and voluntary waiver of the right to counsel, the admission of the defendant’s uncounseled statements to an undercover informant who is secretly acting as a State agent violates the defendant’s Sixth Amendment rights. We disagree with the conclusion that the admission of such statements merely violates a prophylactic rule. Unlike Harris, the State did not simply *607fail to give Ventris Miranda warnings, and, unlike Harvey, the State did not merely interrogate Ventris after his right to counsel had attached. Rather, the State purposely circumvented the requirement for a knowing and voluntary waiver of Ventris’ right to counsel when it recruited Doser to surreptitiously obtain statements from Ventris in his jail cell. Allowing the admission of this testimony as rebuttal evidence would invite the State to engage in clandestine behavior in gathering evidence in violation of our constitutional rights. The purity of justice under our Sixth Amendment’s constitutional right to counsel cannot be polluted by the subversive conduct of deceitful acquisition of evidence.
The State seeks to limit our analysis to whether Ventris’ statements to Doser were voluntary. However, the State’s argument misstates the applicable test for Sixth Amendment violations. Voluntariness of the statement is a test for Fifth Amendment violations. See Hass, 420 U.S. at 722. The test for Sixth Amendment violations is whether the defendant knowingly and voluntarily waived the right to counsel. See Harvey, 494 U.S. at 354. Waiver is valid only when it reflects “ ‘an intentional relinquishment or abandonment of a known right or privilege.’ ” Patterson v. Illinois, 487 U.S. 285, 292, 101 L. Ed. 2d 261, 108 S. Ct. 2389 (1988) (quotingJohnson v. Zerbst, 304 U.S. 458, 464, 82 L. Ed 1461, 58 S. Ct. 1019 [1938]). In this case, there are no facts to support a finding that Ventris knowingly and voluntarily waived his right to counsel even though his statements to Doser may have been voluntary.
In reaching our conclusion that the district court erroneously admitted testimony from a jailhouse informant in this case, we find it necessary to emphasize the fact that the jailhouse informant in this case was recruited to be an agent for the State. The fact that the State initiated the contact with the jailhouse informant and arranged to secretly monitor the defendant’s statements distinguishes this case from a case where the jailhouse informant approaches the State with information and offers to testify against the defendant. We find the State’s conduct to be particularly egregious in this case, particularly because the State knew that its actions violated Ventris’ Sixth Amendment rights. Nevertheless, we do not intend for the rule in this case to deter testimony from all *608informants. Rather, the rule is meant to prohibit the State from recruiting undercover informants to obtain statements once a prosecution has commenced without a knowing and voluntary waiver of the defendant’s Sixth Amendment right to counsel. This rule does not apply when informants approach the State with relevant information that is otherwise admissible.
Ventris properly argues that the district court erroneously admitted testimony from a jailhouse informant who had been surreptitiously placed in Ventris’ jail cell to obtain incriminating evidence. The admission of the evidence violated Ventris’ Sixth Amendment right to counsel. However, an error of constitutional magnitude does not require reversal if it is harmless. The erroneous admission of evidence in violation of a constitutional right is governed by the federal constitutional error rule, which provides that an error is harmless only if the reviewing court is able to declare beyond a reasonable doubt that the error had little, if any, likelihood of changing the outcome of the trial. State v. Hebert, 277 Kan. 61, 96, 82 P.3d 470 (2004).
The jailhouse informant’s testimony directly contradicted Ventris’ version of events. The jury had to decide whether to believe Theel’s story that Ventris masterminded the robbery or Ventris’ story that Theel orchestrated the events in which he was not a willing participant. The jailhouse informant’s testimony was admitted solely to impeach Ventris’ credibility. Although the verdict indicates that the jury did not fully believe Theel, we cannot conclude beyond a reasonable doubt that the admission of the jailhouse informant’s testimony would not have changed the result of the trial. Without the jailhouse informant’s testimony, the jury might have considered Ventris’ story more believable and acquitted him on all of the counts. Accordingly, we must find that the error was not harmless and Ventris’ convictions must be reversed.
Although the first issue is dispositive of Ventris’ convictions, we must address the second issue because it may arise again at Ventris’ next trial. Ventris argues that the district court erroneously admitted Theel’s testimony that Ventris had forcibly strip-searched Theel approximately 1 month before Hicks was killed. Ventris argues that the evidence was admitted in violation of K.S.A. 60-455 without a *609motion or a limiting instruction. According to Ventris, the evidence was highly prejudicial because it implied that Ventris was a dominating partner. The State argues that the evidence was properly admitted as res gestae to explain the relationship between Theel and Ventris.
The Court of Appeals concluded that the district court abused its discretion by admitting the evidence but determined that the error was harmless. Ventris, slip op. at 16. When analyzing a district court’s decision to admit evidence, an appellate court first considers whether the evidence is relevant. Once relevance is established, the court applies the evidentiary rules either as a matter of law or in the exercise of the district court’s discretion, depending on the contours of the rule in question. State v. Gunby, 282 Kan. 39, 47, 144 P.3d 647 (2006). Once relevance has been established, an appellate court reviews the admission of evidence pursuant to K.S.A. 60-455 as a question of law, subject to de novo review. 282 Kan. at 47-48.
Ventris first claims that the evidence could not be admitted because the State failed to file a motion seeking the admission of the evidence. Ventris cites no authority for this claim. Without any supporting argument or authority, we decline to address this argument. See State v. Baker, 281 Kan. 997, 1015, 135 P.3d 1098 (2006).
Next, Ventris asserts that the evidence violated K.S.A. 60-455, which provides:
“Subject to K.S.A. 60-447 evidence that a person committed a crime or civil wrong on a specified occasion, is inadmissible to prove his or her disposition to commit crime or civil wrong as the basis for an inference that the person committed another crime or civil wrong on another specified occasion but, subject to K.S.A. 60-445 and 60-448 such evidence is admissible when relevant to prove some other material fact including motive, opportunity, intent, preparation, plan, knowledge, identity or absence of mistake or accident.”
Pursuant to K.S.A. 60-455, evidence of other crimes and civil wrongs is not admissible if it is not relevant to a disputed material fact. Relevance is established by some material and logical connection between the asserted fact and inference or result it is intended to establish. Gunby, 282 Kan. at 47.
*610The district court admitted the evidence independently of K. S. A. 60-455, relying on the concept of res gestae. However, we put an end to the practice of admitting evidence of other crimes or civil wrongs independently of K.S.A. 60-455 in Gunby. 282 Kan. at 57. We also rejected res gestae as a legal basis for admitting evidence, stating:
“This case provides an opportunity to end this particular confusion of thought, and we hereby do so. The concept of res gestae is dead as an independent basis for admissibility of evidence in Kansas. That evidence may be part of the res gestae of a crime demonstrates relevance. But that relevance must still be measured against any applicable exclusionary rules. Gunby, 282 Kan. at 63.
The Court of Appeals concluded that the trial court committed error. However, the Court of Appeals concluded that the error was harmless. We decline to make that determination at this point. We have already concluded that Ventris is entitled to a new trial on other grounds. If the State seeks admission of this evidence at Ventris’ new trial, the district court must address the test for admitting evidence of other crimes or civil wrongs. Specifically, the district court must determine whether the evidence is relevant to any disputed material fact. If so, the court must then determine whether the evidence is more probative than prejudicial. If the district court concludes that the evidence survives these hurdles, it must give the jury a limiting instruction. See Gunby, 282 Kan. at 56-57.
Because we have reversed Ventris’ convictions and vacated his sentences, we do not need to address his claim that his sentences are unconstitutional because they are dependent on the determination of his criminal history which was not proven beyond a reasonable doubt to a jury.
Davis and Johnson, JJ., not participating. McAnany, J., and Larson, S.J., assigned.