How a Prosecution May Use Expert Testimony to Support Their Case

When defending against Arizona criminal prosecutions, understanding the nuances of expert testimony can be a game-changer in shaping the outcome of a case. The Arizona Court of Appeals recently released a ruling that helps to explain the requirements for a witness in a criminal case to testify as an expert. These standards and requirements may help a skilled attorney exclude harmful evidence from being admitted against their client by a proposed expert.

Expert testimony involves the presentation of opinions or conclusions by individuals with specialized knowledge, skill, experience, training, or education in a particular field relevant to the case. Unlike lay witnesses who testify about facts within their personal knowledge, expert witnesses provide professional opinions to assist the court in understanding complex issues.

The recently decided opinion involved a case where the defendant appealed convictions for aggravated assault, and the victim testified as to the source of damage to a vehicle. On appeal, the defendant argues that this was expert testimony that was improperly admitted at trial. In the recently released opinion, the appellate court discussed the factors that define expert testimony versus lay testimony.

Testimony from lay witnesses must be rationally based on their perception of events, helpful in understanding the case, and not reliant on specialized knowledge beyond their expertise. Witnesses who testify as to scientific or technical knowledge must be qualified as experts. Expert testimony is based on scientific, technical, or specialized knowledge within the scope of the relevant legal standards. However, it must also be rooted in the witness’s perception and helpful in determining facts in the case.

In the case discussed in the judicial opinion, the court addressed the admissibility of testimony regarding damage to a tow truck allegedly caused by bullets. The court determined that the witness’s testimony was that of a lay witness, not an expert, as it was based on their perception of events and did not rely on specialized knowledge beyond their expertise.

While not every case involves expert witness testimony, in those that do, it is imperative to have an experienced attorney at your side to review the testimony and ensure the judge instructs the jury appropriately. Otherwise, you run the risk of the jury assigning too much credibility to the testimony.

Challenging and Utilizing Expert Witness Testimony in Your Case

Understanding the requirements for expert testimony is crucial for mounting a strong defense. Whether challenging the admissibility of opposing expert testimony or leveraging expert witnesses in your favor, strategic decision-making can significantly impact the outcome of your case. If you are facing criminal charges in Arizona, it is imperative to understand the legal implications of expert testimony and seek competent legal representation to navigate such complexities. The skilled Arizona criminal defense attorneys at the Law Office of James E. Novak are experienced in handling many types of criminal charges, including violent crimes. With our experience, you can be confident you’ll have the best chance of successfully defending against whatever charges have been brought against you. Contact us now at 480-413-1499 to schedule a no-obligation consultation to discuss your case.