In a prosecution for assault, using a dangerous weapon during the commission of a crime of violence, and threatening a witness, the trial court committed reversible error by denying the defendant's motion for a new trial without first conducting a hearing to investigate possible juror misconduct. In this case the defendant alleged that one of the jurors informed the other members of jury panel that defendant and a co-defendant had killed an individual victim and gotten away with it. There was no evidence presented at trial, however, to suggest that either of the defendants was involved in that death, and thus the statements the juror allegedly communicated were extraneous information-matter considered by the jury but not admitted into evidence. Accordingly, Federal Rule of Evidence 606(b) did not prohibit the trial court from holding an evidentiary hearing to determine whether this extraneous information was improperly brought to the jury's attention, and, if so, whether it affected the verdict. The trial court also incorrectly concluded that defense counsel's affidavit was wholly insufficient to warrant an evidentiary hearing. In determining whether an evidentiary hearing is necessary, a trial court should consider numerous factors, including the content of the allegations, the seriousness of the alleged misconduct or bias, and the credibility of the source. While a signed affidavit from the juror personally would have been preferable, denying the motion for a new trial without conducting even a limited evidentiary hearing regarding jury misconduct was an abuse of discretion, given the specific allegations of jury misconduct, the fact that inquiry could have been limited as provided in Rule 606(b) to whether extraneous prejudicial information was improperly brought to the jury's attention, and the fact that the attorney's affidavit was given by an officer of the court under oath and penalty of perjury. Based on these factors, the trial court should have, at a minimum, held a limited evidentiary hearing to allow the juror to testify whether any extraneous prejudicial information was improperly brought to the jury's attention. This matter is therefore remanded to the Superior Court for an evidentiary hearing.