In a case from New York called People v. LeGrand, the issue was whether the trial judge was correct in refusing to admit expert testimony regarding the reliability of eyewitness identifications. In refusing to admit such testimony, the judge in the LeGrand case ruled the same way that most judges throughout the United States rule when it comes to this particular issue.
The relevant facts in LeGrand are as follows:
On the morning of June 15, 1991, a cab driver named Joaquin Liriano was stabbed to death in Manhattan. The person who stabbed Liriano ran away before the police arrived. Four people witnessed the attack and within a few days collaborated on a composite sketch of the person who stabbed Liriano.
Two years later, Nico LeGrand was identified as a possible suspect in the killing when an officer who arrested him on an unrelated burglary charge concluded that he resembled the 1991 composite sketch. However, because the police were unable to find any of the witnesses to the stabbing, the murder case stalled. The case remained inactive until April 1998 when LeGrand was again arrested for burglary in the same precinct. Police again concluded that he resembled the composite sketch.
This time the police located the four witnesses who contributed to the composite sketch as well as one additional witness to the stabbing who was not identified until 1998. One of the witnesses identified LeGrand as the killer in a photo array and a lineup. Two of the remaining witnesses were shown the photo array, but neither made a positive identification. Specifically, one witness picked out LeGrand's picture as a "close, if not exact" match. A third witness described LeGrand's picture as "similar" to that of the man who had stabbed the taxi driver. The fourth and fifth witnesses also examined the photo array but were unable to identify LeGrand. There was no forensic or other physical evidence connecting LeGrand to the stabbing.
In April 1999, LeGrand was charged with second-degree murder. The prosecutor's case rested solely on identifications made nearly seven years after the crime. In April 2001, during LeGrand's first trial, three witnesses identified him as the person who stabbed the cab driver. However, two of the witnesses had seen LeGrand's photo array in the district attorney's office the night before they were to testify. This first trial ended in a mistrial (due to a hung jury) after three days of deliberation.
Prior to his second trial in June 2001, LeGrand asked the judge for permission to present to the jury the testimony of an expert in order to "educate the jurors as to the weaknesses and dangers inherent in eyewitness testimony and to present them with an appropriate perspective by which to judge such testimony." According to LeGrand, the expert would testify about research findings regarding several factors that could influence the perception and memory of a witness and affect the reliability of eyewitness identifications. More specifically, he would testify about:
1. The effect of "weapon focus;"
2. The lack of correlation between how confident an eyewitness is and the accuracy of her identification; and
3. The effect of post-event information on the accuracy of an eyewitness identification as well as the confidence of the eyewitness.
The expert would not, however, give an opinion as to the accuracy of any specific eyewitness identification in LeGrand's case.
The prosecutor opposed LeGrand's request on the ground that such theories were "highly controversial." The prosecutor also argued that cross-examination and/or the jury instructions that would be given by the judge could counter a mistaken identification.
The judge denied LeGrand's request because, in his opinion, the expert's conclusions were not generally accepted in the relevant scientific community (presumably composed of psychologists). The jury ultimately found LeGrand guilty of second-degree murder, and he was sentenced to 25 years to life in prison.
have been allowed to present the expert testimony that he had requested. The appellate
court stated that where the case turns on the accuracy of eyewitness identifications and there is little or no corroborating evidence connecting the defendant to the crime, a judge should not exclude expert testimony on the reliability of eyewitness identifications if that testimony is:
1. Relevant to the witness' identification of the defendant;
2. Based on principles that are generally accepted within the relevant scientific community;
3. Presented by a qualified expert; and
4. Presented on a topic that is beyond the understanding of the average juror.