                  that Perez testified on cross-examination that becoming a convicted felon

                  would affect his employment as an electrician and general foreman in the

                  union where he makes $43 an hour, result in the loss of his clearance for

                  entering vaults and other high-security areas in casinos, and impact the

                  custody of his child. The State argues that the fact that Perez lied to the

                  police during the collateral incident was relevant to show that he will do

                  anything to prevent a criminal conviction and to otherwise protect his job

                  and his status as the primary custodian of his child.

                              "We review a district court's decision to admit or exclude

                  evidence for an abuse of discretion." Mclellan v. State, 124 Nev. 263, 267,

                  182 P.3d 106, 109 (2008). "An abuse of discretion occurs if the district

                  court's decision is arbitrary or capricious or if it exceeds the bounds of law

                  or reason." Crawford v. State, 121 Nev. 744, 748, 121 P.3d 582, 585 (2005)

                  (internal quotation marks omitted).

                              Whenever a criminal defendant takes the witness stand, he

                  becomes a witness and places his credibility at issue.       See 2 Wharton's

                  Criminal Evidence § 9:21 (15th ed. 1997). The State is permitted to

                  impeach a defendant's credibility by inquiring into collateral matters on

                  cross-examination "with questions about specific acts as long as the

                  impeachment pertains to truthfulness or untruthfulness and no extrinsic

                  evidence is used."   Ford v. State, 122 Nev. 796, 806, 138 P.3d 500, 507

                  (2006) (quoting Collman v. State, 116 Nev. 687, 703, 7 P.3d 426, 436

                  (2000)); see NRS 50.085(3). However, the collateral matter in this case

                  does not plainly pertain to truthfulness. The fact that Perez told a police

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                  officer that he had no reason to burglarize cars and later pleaded guilty to

                  tampering with cars does not demonstrate he was untruthful because the

                  crime that he denied and the crime that he admitted to are two different

                  crimes.   See NRS 200.060 (defining burglary); NRS 205.274 (defining
                  tampering with cars). Therefore, we conclude that the district court

                  abused its discretion by allowing the State to cross-examine Perez

                  regarding this collateral matter.

                               The State also is not permitted to impeach a defendant with

                  extrinsic evidence of collateral matters unless the "extrinsic evidence [is]

                  relevant to prove [the defendant's] motive to testify in a certain way, i.e.,

                  bias, interest, corruption or prejudice." Lobato v. State, 120 Nev. 512, 519,

                  96 P.3d 765, 770 (2004). Here, the collateral fact that Perez may have lied

                  to a police officer during an unrelated investigation in another case does

                  not demonstrate or even suggest that Perez had motive to testify in a

                  certain manner in this case. Instead, it has the effect of improperly

                  impeaching Perez's credibility by contradicting his cross-examination

                  testimony.   See id. ("NRS 50.085(3) limits the admissibility of extrinsic
                  evidence for the purpose of attacking credibility based upon specific

                  instances of conduct attributable to the witness. Unless in some way

                  related to the case and admissible on other grounds, extrinsic prior bad act

                  evidence is always collateral and therefore inadmissible to attack

                  credibility."). Therefore, we conclude that the district court abused its

                  discretion by allowing the State to present rebuttal evidence regarding

                  this collateral matter.

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                   Harmless error analysis
                                Perez claims that the error in admitting extrinsic evidence of

                   the collateral incident was not harmless because the record plainly

                   demonstrates that the district court and the parties believed that the

                   admission of this evidence would likely have a strong influence on the

                   jury's verdict. The State acknowledges that there is no dispute that the

                   trial boiled down to credibility, but it argues that any error was harmless

                   because Perez's story changed on numerous occasions, his testimony did

                   not match the physical evidence, and his testimony did not support his

                   theory of self-defense.

                                "A nonconstitutional error, such as the erroneous admission of

                   evidence at issue here, is deemed harmless unless it had a substantial and

                   injurious effect or influence in determining the jury's verdict."   Newman v.

                   State, 129 Nev. , 298 P.3d 1171, 1181 (2013) (internal quotation
                   marks omitted). The record on appeal—including the recordings of the

                   311 and 911 calls and Perez's police interview—demonstrates that this

                   was a close case. As the jury's verdict hinged almost entirely upon its

                   assessment of the witnesses' credibility, we cannot say that the district

                   court's error was harmless.

                   Motion for mistrial
                                Perez claims that the district court erred by denying his

                   motion for a mistrial after the State's rebuttal witness improperly testified

                   that he had previously spoke with Perez while investigating "an auto

                   burglary." However, we need not reach this issue because, as set forth

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                   above, the introduction of improper impeachment evidence was not

                   harmless and mandates reversing the judgment of conviction and

                   remanding the case for a new trial.

                                  Accordingly, we

                                  ORDER the judgment of the district court REVERSED AND

                   REMAND this matter to the district court for proceedings consistent with

                   this order.'



                                             Pickering


                                               , J.
                   Parraguirre                               Saitta




                   cc:   Hon. Michelle Leavitt, District Judge
                         Justice Law Center
                         Attorney General/Carson City
                         Clark County District Attorney
                         Eighth District Court Clerk




                         'The fast track statement does not comply with the formatting
                   requirements of NRAP 3C(h)(1) and NRAP 32(a)(4) because it is not
                   paginated. We caution appellant's counsel that failure to comply with the
                   applicable rules when filing briefs in this court may result in the
                   imposition of sanctions. See NRAP 3C(n).


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