This article presents case examples regarding police officer testimony as viewed by three different appellate courts.
Police officers may testify as an expert witness in one case and a lay witness in another. However there has been some debate as to whether an officer can offer both kinds of testimony in the same trial; in other words, whether a policeman can wear "two hats" on the witness stand. The first case, Eason v. United States, presents an evolution in one court's view of dual testimony. The District of Columbia Court of Appeals held that there should not be a per se ban in criminal trials against dual expert and lay testimony from a single witness. Instead the court of appeals held that the decision should be left to the trial court's discretion in each case whether the danger of jury confusion could be neutralized by lesser measures than exclusion of dual testimony altogether. The second case, United States v. Dukagjini provides an indepth assessment of the problems created when a law enforcement officer testifies as both an expert and a lay witness. In its analysis the appellate court reviewed some of the risks intrinsic in the dual role context: the designation as an expert confers an aura of trustworthiness and special reliability upon the witness, which could cause the factfinder to give the witness's lay testimony unmerited credibility. Attorneys might be reluctant to cross-examine a fact witness about their expert testimony because an unsuccessful impeachment attempt could actually bolster the credibility of the witness's lay testimony. There is an increased risk that the expert will exceed the scope of permissible testimony and convey "sweeping conclusions" about the defendant. The last example, United States v. Freeman, illustrates one of the most recent cases on the issue. The Ninth Circuit also reiterated the Second Circuit's decision not to categorically ban such dual testimony. References
Date Published: October 1, 2007