concurring specially. While I agree with the result reached by the majority, I believe that the trial court erred by admitting into evidence detailed testimony from Siegel regarding the abuse she suffered at the defendant’s hands, including testimony that the defendant *653repeatedly attacked her with a taser stun gun, once while she was showering.
New Hampshire recognizes that evidence of other crimes, wrongs or acts is typically inadmissible as character evidence, but that it may be admissible for other purposes, such as “proof of motive, opportunity, intent, preparation, plan, knowledge, identity, or absence of mistake or accident.” N.H. R. Ev. 404(b). As the majority notes, there is a three-part test for admissibility under Rule 404(b): (1) the evidence must be relevant for a purpose other than proving the defendant’s character or disposition; (2) there must be clear proof that the defendant committed the act; and (3) the probative value of the evidence must not be substantially outweighed by its prejudice to the defendant. State v. Smalley, 151 N.H. 193, 196 (2004).
The defendant did not challenge the admission of general evidence that he was abusive to Siegel and that she was afraid of him. While evidence that Siegel was abused by and afraid of the defendant was, arguably, relevant to explaining Siegel’s conduct, evidence detailing the defendant’s savagery in inflicting the abuse was not. Such evidence, including Siegel’s testimony that the defendant assaulted her on numerous occasions with a taser gun, could be relevant only to show that the defendant was a man of despicable and violent character, and was plainly offered for that purpose.
I disagree with the majority’s conclusion that this evidence was admissible under Rule 404(b) to explain Siegel’s submission to the defendant, because I do not believe that “explaining witness submission” is a category contemplated for admissibility under Rule 404(b). In my view, cataloging the incidents and behavior underlying a witness’s submission to a defendant can only be considered evidence of the defendant’s character or propensity to commit the charged crime.
Moreover, I do not believe that Rule 404(b) contemplates the admission of evidence prejudicial to the defendant simply because it is relevant to a witness’s credibility as the trial court found. In State v. Berry, 148 N.H. 88 (2002), we considered whether evidence demonstrating that the defendant abused his adopted daughter and created an atmosphere of fear in his family’s household was admissible, under Rule 404(b), to explain the daughter’s delay in reporting sexual abuse suffered at the hands of the defendant. Id. at 92. We held that it was. Id. In Berry, however, the conduct portrayed by the evidence (physical abuse) did not tend to demonstrate a propensity towards the conduct for which the defendant was being tried (sexual assault). In the instant case, the proffered evidence tended to reinforce the notion that the defendant was inclined to commit the violent act for which he was being tried. I believe that the position taken by the majority may allow prosecutors to bolster the credibility of a *654dubiously reliable witness while simultaneously gaining the admission of prejudicial propensity evidence. Such a result would undermine the purpose of Rule 404(b).
I believe that Siegel’s testimony detailing the defendant’s violent acts towards her fails the first and third prongs of the three-part test. As such, I believe that the trial court should have found it inadmissible pursuant to Rule 404(b).
Nevertheless, it is my opinion that the trial court’s error was harmless. The harmless error standard is as follows:
In determining the gravity of an error, this court asks whether it can be said beyond a reasonable doubt that the inadmissible evidence did not affect the verdict. The evaluation of whether this standard has been achieved involves consideration of the alternative evidence presented at trial and of the character of the inadmissible evidence itself. An error may be harmless beyond a reasonable doubt if the alternative evidence of the defendant’s guilt is of an overwhelming nature, quantity, or weight and if the inadmissible evidence is merely cumulative or inconsequential in relation to the strength of the State’s evidence of guilt.
State v. Enderson, 148 N.H. 252, 255 (2002) (quotation omitted). The State bears the burden of proving harmless error. Id.
Here, the alternative evidence of the defendant’s guilt was overwhelming. This case involved a ten-day trial with over twenty-five witnesses. The evidence included detailed testimony from key witnesses regarding the defendant’s conduct surrounding the murders. The jury heard testimony from both Siegel and Badeau about the events that took place in the parking lot. In addition, both testified about the defendant’s conduct leading up to and following the murders. The jury heard evidence of the defendant’s effort to obtain a gun prior to the murders and his admissions to Goupil immediately following the murders. Moreover, the jury heard the defendant’s own lies to police about his involvement in the murders, which were directly contradicted by his cellular phone records and other evidence that placed him at the scene of the murders. After a review of the record, I am convinced beyond a reasonable doubt that the jury would have convicted the defendant without the evidence of the abuse. Accordingly, I believe that the trial court’s error was harmless, and I concur in the result.