Pennsylvania Rule of Evidence 404(a)(2) permits a defendant in a criminal case to offer reputation and specific-act evidence [405(b)(2)] of the complaining witness (victim's) pertinent trait or traits. When a defendant does so, the prosecutor may offer reputation evidence of the defendant's same pertinent trait or reputation evidence of the complainant's character trait.

For example, in assault or homicide cases, the defendant may offer evidence of the victim's character for violence and aggression. This evidence may be used to show that defendant reasonably believed that his or her life was in danger to support a claim for self-defense. Commonwealth v. Dillon, 598 A.2d 963 (Pa. 1991). When offered as evidence of the defendant's state of mind, however, there must be some showing that the defendant knew of the violent character. Commonwealth v. Darby, 373 A.2d 1073 (Pa. 1977).

Once again, specific act evidence is admissible under 405(b)(2). Evidence of the complainant's violent character is admissible to prove the complainant's aggressive character, which can include reputation for violence and violent behavior against the defendant and 3rd parties and/or whether the defendant was aware of the acts.

However, after the defendant offers such evidence (through either a witness or questioning the complainant about it), the Commonwealth is permitted to rebut this evidence by providing reputation evidence for peacefulness [404(a)(2)(i)] or evidence of the defendant's reputation for aggressive behavior [404(a)(1)].

In civil cases, there are some other considerations. Pertinent trait evidence of character is almost always inadmissible in civil cases [404(a)]. Still, a witness's character for untruthfulness and truthfulness may be impeached or rehabilitated as provided in Rule 608 and Rule 609. A Plaintiff's character for violence or aggression may be shown in support of self defense [404(a)(2)(i)]. Similarly, a civil defendant who is sued for assault and battery may offer evidence of the plaintiff's violent character to prove the plaintiff was the aggressor [404(a)(2)(iii)].