In Brown v. Commonwealth, 6 Va. App. 82, 86, 366 S.E.2d 716, 719 (1988) the Court found the trial court erred in allowing the Commonwealth to impeach its witness when he changed his testimony, claiming on the stand that he did not see the stabbing and did not know the parties. This testimony, although contradicting the witness' previous statement to the police, "had no probative value as it could not have assisted the trier of fact in determining Brown's guilt or innocence." Id. The testimony given by the witness did not prove or disprove Brown's guilt; instead, it added nothing to a description of the events.