Wis. Stat. § 904.05
A detective's opinion of a drug addict's reputation for truth and veracity did not qualify to prove reputation in the community because it was based on 12 varying opinions of persons who knew the addict, from which a community reputation could not be ascertained. Edwards v. State, 49 Wis. 2d 105, 181 N.W.2d 383 (1970). When a defendant's character evidence is by expert opinion and the prosecution's attack on the basis of the opinion is answered evasively or equivocally, then the trial court may allow the prosecution to present evidence of specific incidents of conduct. King v. State, 75 Wis. 2d 26, 248 N.W.2d 458 (1977). In order for specific acts of violence to be admissible, "character or a trait of character of a person" must be "an essential element of a charge, claim, or defense." In a homicide case in which a claim of self-defense is raised, character evidence may be admissible as evidence of the defendant's state of mind so long as the defendant had knowledge of the prior acts at the time of the offense. State v. Jackson, 2014 WI 4, 352 Wis. 2d 249, 841 N.W.2d 791, 11-2698. Self-defense prior acts of the victim. 1974 WLR 266.