dissenting.
¶ 83 I agree with Parts I, II, ILA, and IIIB of the majority opinion. I respectfully dissent from Part III. C, the portion of the opinion affirming the judgment of conviction on the basis of harmless error. Instead, I would, as the original opinion concluded, reverse the conviction and remand for a new trial.
¶ 84 There is no dispute that defendant, through counsel, lodged appropriate objections to the introduction of the other acts evidence. Having concluded that the admission of the other acts evidence was error, this division is next asked to determine whether the introduction of that evidence prejudiced defendant. Error is deemed harmless where there is no reasonable probability that the error contributed to the defendant's convietion by substantially influencing the verdict or impairing the fairness of the trial. People v. Jones, (Colo.App.2011) (cert. granted 2012 WL 1820863 (May 21, 2012)); see also Yusem v. People, 210 P.3d 458, 469 (Colo.2009) (recognizing that the proper inquiry is not whether "there was sufficient evidence to support the verdict without the improperly admitted evidence, but, rather, whether the error substantially influenced the verdict or affected the fairness of the trial proceedings" (quoting People v. Gaffney, 769 P.2d 1081, 1088 (Colo.1989))). The majority concludes that the error was harmless. I must, respectfully, disagree.
¶ 85 In a child abuse case like this, where emotions are especially heightened, the reasonable probability that the other acts evidence would sway a jury is unmistakable. See Montgomery v. State, 810 S.W.2d 372, 397 (Tex.Crim.App.1990) (recognizing the inherently inflammatory nature of evidence of misconduct involving children); State v. Miller, 1999 WL 1240911, *3 (Wis.Ct.App. No. 98-3546-CR, Dec. 22, 1999) (unpublished table decision) (recognizing that allegation of child abuse is "inflammatory" and appeals to "the jury's natural revulsion" against such abuse). The majority recognizes as much, referencing studies that indicate that "the admission of a defendant's uncharged misconduct significantly increases the likelihood of a jury finding of liability or guilt" because the defendant is stigmatized and the jury is predisposed "to find him liable or guilty." See also People v. Lewis, 69 N.Y.2d 321, 514 N.Y.S.2d 205, 506 N.E.2d 915, 916-17 (1987) (recognizing that "juries attribute too much significance" to prior acts evidence).
¶ 86 The danger that other misconduct, independent of the charged crime, can bias a jury forms the basis of fundamental principles of our legal system, including that
a person is tried only for those crimes with which he has been charged; the penalties of criminal law are appropriately imposed only for the unlawful activity charged, not for bad character or predisposition; [and] admissible evidence at trial is generally limited to proof of [those] events which form the bases of the charges.
Ali v. United States, 520 A.2d 306, 309 (D.C.1987).
¶ 87 Because defendant was the only person with the child the day of her injuries, the case is necessarily based on circumstantial evidence. Thus, both sides relied on various experts, including forensic experts, to persuade the jury what happened to the child, how it happened, and who was responsible.
¶ 88 Most of the doctors' trial testimony focused on the injuries to the child. Con-cededly, there was overwhelming evidence *225about those injuries The evidence was, however, weakest on the cause of those injuries. Throughout trial, defendant's counsel focused on persuading the jury that J.C.'s injuries were accidental or were not caused by defendant, while the prosecution focused on proving that defendant non-accidentally caused J.C.'s injuries.
1 89 Without the benefit of the jury's deliberations, which are necessarily confidential, it is impossible to know how the trial would have ended based on the expert opinion alone, and without the "other acts" evidence. See generally, Yusem, 210 P.8d at 470 (analyzing whether the admission of other acts evidence was reversible error and concluding that prejudicial evidence that discredited defendant's testimony "may have unfairly tipped the seales in favor of the People"); see also People v. Salazar, 2012 CO 20, 1 27, 272 P.3d 1067 (concluding that the trial court abused its discretion in granting the defendant's motion to introduce evidence of an alternative suspect's prior sexual conduct, in part because of the risk of confusion of the issues material to the case) The record shows, however, that defendant and his counsel knew from the start that the trial court would allow evidence of the two 2006 dissimilar incidents against A.C. that occurred more than three years before defendant's trial and more than five months before J.C.'s injuries. That evidence was extremely damaging and largely unconnected to the current charges related to J.C. See, eg., Kaufman v. People, 202 P.3d 542, 555 (Colo.2009) (although defendant collected knives, his collection did not include a knife like the one used in the altercation at issue; thus, the court concluded that it was inappropriate for the prosecution to parade "evidence before the jury merely to paint a picture of [defendant] as a bad person"); State v. Price, 80 Ohio App.3d 35, 608 N.E.2d 818, 822 (1992) (concluding that admission of evidence of defendant's sexual conduct with an older stepdaughter, which did not involve the vietim of the eur-rent charges, was inadmissible and prejudicial where it was not "so connected with the acts for which [defendant] was convicted that proof of one incidentally involves the other").
€T90 So damaging was the evidence that defendant's counsel opened the case by asking the jury not to judge the then twenty-one-year-old defendant by whether his eighteen-year-old girlfriend's family liked him or by whether that same family accused him of mistreating A.C., who was about three years older than J.C. and was injured in a different manner and under different cireumstances many months earlier.
191 As the majority agrees, the trial court's admission of these two separate incidents against A.C. was improper. See also Shepard v. United States, 290 U.S. 96, 104, 54 S.Ct. 22, 78 L.Ed. 196 (1983) (noting, before the adoption of the Federal Rules of Evidence, the extent of judicial discretion to admit or exclude evidence: "When the risk of confusion is so great as to upset the balance of advantage, the evidence goes out."). First, J.C. and A.C.'s maternal grandfather testified that, in June 2006, he observed defendant slap A.C. on the cheek, while arguing with A.C.'s aunt, leaving a red handprint that later turned into a bruise. Next, J.C.'s and A.C.'s maternal great-grandmother was allowed to testify that at a family function, which occurred many months before J.C. was injured, she saw defendant holler at his girlfriend, the children's mother, and he then grabbed A.C. by the arm, threw her into the car, and smacked her in the arm before leaving. The prosecutor immediately followed that graphic testimony by asking the great-grandmother whether she went to the hospital on October 7, 2006, to see J.C., without making a clear distinction between A.C. and J.C. The jury then could have easily confused - defendant's observed - conduct against A.C. with the circumstantial evidence surrounding J.C.'s injuries. See Michelson v. United States, 885 U.S. 469, 475-76, 69 S.Ct. 218, 98 L.Ed. 168 (1948) (recognizing that, even when the evidence is probative, the "overriding policy of excluding such evidence ... is the practical experience that its disallowance tends to prevent confusion of issues, unfair surprise and undue prejudice").
T92 Despite defense counsel's efforts to show that other people had access to J.C. in the days before she was injured and that defendant's interactions with J.C. were play*226ful rather than intended to harm her, the jury's impartiality had been irreversibly contaminated with the suggestion that defendant was a child abuser (by having struck the older child on two separate unrelated prior oceasions in a manner different from the injury to J.C.) with a bad temper (by having "hollered" at the girlfriend). See State v. Fername, 185 Ariz. 222, 914 P.2d 1814, 1318-19 (App.1995) (concluding that the trial court abused its discretion in admitting other highly prejudicial evidence related to abuse and injuries sustained by defendant's other children in a child abuse and felony murder case relating to abuse of her two-year-old younger child); Price, 608 N.E.2d at 822.
T93 Because I cannot say that the other acts evidence did not impair the fairness of this trial or that there was a reasonable probability that the erroneously admitted evidence did not contribute to this conviction, I would reverse and remand for a new trial. Yusem, 210 P.3d at 469; Jones, 2012 WL 1820863; see also Strickland v. Washington, 466 U.S. 668, 694, 104 S.Ct. 2052, 80 L.Ed.2d 674 (1984) (noting that a reasonable probability "is a probability sufficient to undermine confidence in the outcome").