In Massachusetts criminal trials, evidence presented by the state must be relevant to the case, but not all relevant evidence is automatically admissible. The court must weigh whether the evidence’s probative value—its ability to prove something important—is greater than its potential to unfairly prejudice the jury against the defendant. Certain evidence does not have enough probative value to counteract the risk of unfair prejudice to a defendant, so the Rules of Evidence may prohibit its admission.
A recent appellate decision involved a defendant convicted of domestic violence. The prosecution had evidence of other uncharged violent acts by the defendant against the victim, which they argued was relevant to show the defendant’s intent and the hostile nature of the relationship. The defendant objected, claiming this evidence would unfairly bias the jury against him. The trial court decided to exclude some of this evidence while allowing other parts in. The jury, after hearing the admitted evidence, convicted the defendant, who then appealed the decision, arguing that the inclusion of the prior bad acts was prejudicial and should have been excluded entirely.
In Massachusetts, the rules regarding the admission of prior bad acts are specific. Such evidence can be allowed if it helps demonstrate a common pattern, intent, or absence of mistake, but it must be carefully weighed against the potential for undue prejudice. In this case, the trial judge provided instructions to the jury to limit the impact of the prior bad acts evidence, emphasizing that it should not be used to infer the defendant’s bad character but rather to consider specific aspects like intent or motive. The appellate court upheld the trial court’s decision, noting that the instructions were clear and effective in mitigating any potential prejudice. They further noted that the jury’s ability to acquit the defendant of some charges indicated they were not unduly swayed by the prior bad acts evidence.