Jury instructions regarding expert witnesses are outlined in Maine’s Pattern Criminal Jury Instructions, rule 3.06. ME. PATTERN CRIM. JURY INSTR. 3.06 (2002). This rule instructs the jury that it does not have to accept the testimony of any witness if it does not feel the witness is credible. Id. The jury has the duty to consider all of the testimony and decide what witnesses to believe and give credibility to. Id. When evaluating what witnesses to believe, the jury should consider the witness’s “conduct and demeanor while testifying,” whether the witness has bias or prejudice, if the witness is an interested witness, and “their opportunities for seeing and knowing the things about which they have testified.” Id. Additionally, the jury should consider how reasonable the witness’s testimony is and whether there was other evidence presented that either supports or contradicts the witness’s testimony. Id.
