In O'Donnell v. State, 200 Ga. App. 829 (409 SE2d 579) (1991), the Court found no abuse of discretion where the trial court allowed a district attorney's investigator to be qualified as an expert witness in drug distribution, where the investigator "had collected and viewed evidence found in the possession of people involved in drug transactions in dozens if not hundreds of occasions." Id. at 834 (2).