Criminal defendants often wonder whether their good character or reputation will help convince a jury they are innocent of the charges against them. Alternatively, defendants worry their previous misconduct may be used against them. While evidence of good (or bad) character is generally prohibited, there are some important exceptions that allow such evidence to be admissible.
What happens when a defendant is arrested and charged with beating up his wife, and he has been accused of beating her up repeatedly in the past? What if he has been formally charged and convicted of assault and battery? These facts would constitute powerful evidence for the prosecutor. However, Massachusetts law does not allow a prosecutor to offer evidence of the defendant’s prior bad acts to establish he has bad character or the propensity to commit a crime. When can prior bad act evidence be introduced to the jury?
When its purpose is to establish:
Prosecutors love prior bad act evidence, because outlining a history of abuse committed by a defendant in front of a jury is compelling. When a judge allows a prosecutor to admit prior bad acts at a trial, it can cripple a defendant’s case.
In some cases, judges will allow a defendant to introduce the prior bad acts of the alleged victim for the same reasons they may be admitted against a defendant as outlined above. Further, when a defendant is accused of assaulting the alleged victim, and the alleged victim has her own history of committing assaults, the alleged victim’s history of violence might be admissible to establish the identity of the “first aggressor.” This often happens in cases where the defendant is asserting he acted in self-defense. If the alleged victim has previously assaulted the defendant (or anyone, for that matter), the judge will likely allow the defendant to present that evidence to the jury.
In a criminal trial, the defendant may introduce evidence of his own good character to establish he is not the type of person who would have committed the crime with which he is charged. The only type of admissible character evidence is reputation evidence (rather than specific act evidence). The character traits must be relevant to the crime – for example, a defendant charged with assault and battery may introduce evidence that he has a reputation for being peaceful. A defendant charged with embezzlement may introduce evidence that he has a reputation for being honest.
Introducing evidence of a defendant’s good character is dangerous. Once a witness has testified the defendant has a reputation for a good character trait, the prosecutor can ask the witness questions about specific prior bad acts of the defendant that are inconsistent with good character. The door opens for otherwise inadmissible bad act evidence against the defendant to be introduced to the jury.