Brief Fact Summary. The defendant, Dolan Chapple (the “defendant”), was convicted of three counts of murder primarily based on an eye witness identification. The defendant claimed he was out of state at the time of the murders, and witnesses testified in his support. He offered an expert on eye witness testimony during trial to support his claim of mistaken identify, but the trial court did not allow the expert testimony.
Synopsis of Rule of Law. Expert testimony may be admitted if the scientific, technical, or other specialized knowledge will assist the trier of fact in understanding evidence or determining a fact in issue.
Photographs may be relevant to prove the corpus delicti, to identify the victim, to show the nature and location of the fatal injury, to help determine the degree or atrociousness of the crime, to corroborate state witnesses, to illustrate or explain testimony, and to corroborate the state's theory of how and why the homicide was committed.View Full Point of Law
Issue. Did the trial court abuse its discretion in not allowing the testimony of the defendant’s expert on eyewitness identification?
Held. Justice Feldman issued the opinion for the Supreme Court of Arizona, holding that the trial court did abuse its discretion in not allowing the expert testimony.
Dissent. Justice Hays dissents because he believes the Court has “opened the door” to testimony attacking other supposed or real deficiencies regarding mental abilities. He believed the ruling disturbs the fact-finding role of the jury.
Discussion. Four criteria should be applied in order to determine the admissibility of an expert on eyewitness testimony: 1) qualified expert; 2) proper subject; 3) conforms to a generally accepted explanatory theory; and 4) probative value compared to prejudicial effect. The State conceded that the defendant’s expert met the first and third criteria, thus the Supreme Court of Arizona only examined the proper subject and probative value issues criteria. The opinion notes that the expert’s testimony in this case was beyond the knowledge of the average juror and would assist the jury in determining the issues before them. Proper identification was the most important issue in the case, and the opinion illustrates that based on the facts in the case, the testimony might have assisted the jury in resolving some of the fact issue without being unfairly prejudice to the prosecution.