Forensic Animations & Demonstrative Exhibits – A Quick Guide

Forensic Animations & Demonstrative Exhibits — A Quick Guide

Why That Famous Line ‘If the Glove Doesn’t Fit, You Must Acquit’ Violates the Rules of Evidence

One of the most iconic statements ever made by a criminal defense attorney in modern American history was delivered by the legendary Johnny Cochran during the closing arguments of the O.J. Simpson trial: ‘if the glove doesn’t fit, you must acquit.’

As memorable as that phrase is, it also serves as a textbook example of a violation of one of the foundational principles in evidentiary law — the doctrine of substantial similarity. The glove in question had been soaked in blood and allowed to dry for weeks prior to being introduced as a demonstrative exhibit. It had shrunk and hardened — rendering it no longer in a condition substantially similar to how it would have been at the time of the alleged crime. Even though the defense presented the actual glove from the crime scene as demonstrative evidence, any attempt to have the defendant try it on in court should have carried little to no evidentiary weight under proper legal standards.

That brings us to today’s topic — the evidentiary standards of forensic animations and demonstrative evidence, their purposes, methods and admissibility in court.

Forensic Animations vs. Demonstrative Evidence

Forensic Animation

Forensic animation covers a broader scope of cases — it can be introduced without extensive expert testimony if the exhibit is readily understandable. Forensic animations vary in complexity, from simple charts to intricate models or animations.

Purpose

• Forensic evidence is a specialized form of demonstrative evidence
• It’s a visual representation, often computer-generated, that recreates events based on witness testimony, physical evidence or expert opinions
• Forensic animation aids lawyers, legal teams, jurors and investigators in understanding complex scenarios.

Methodology

• Forensic animations are built upon the input of witnesses, experts and collected data like accident reports, photographs, witness statements, court documents, camera footage and more.

Admissibility

• Like other forms of demonstrative evidence, forensic animations must meet the criteria of relevance, accuracy and helpfulness to be admissible in court. They are generally admissible as demonstrative aids if they fairly and accurately portray the evidence they are intended to illustrate and are not misleading. However, they are generally not considered independent substantive evidence — they supplement existing evidence and support witness testimony

Demonstrative Evidence

Demonstrative evidence covers a slimmer scope of cases, it typically relies heavily on witness testimony or expert opinion to establish the basis and accuracy of the animation. It’s often used for complex events involving motion, timing and spatial relationships that are difficult to explain verbally.

Purpose

• Demonstrative evidence is any exhibit or device used to illustrate or clarify a fact in a case
• It can support oral testimony or recreate an occurrence
• It can help recreate an occurrence, show how an event may have happened, highlight relationships between people or objects, or illustrate scientific or technical data in a way that words alone might not convey effectively.

Types

• Demonstrative evidence includes a wide range of materials, such as photographs, videos, charts, diagrams, graphs, models and forensic animations

Admissibility

• For demonstrative evidence to be admissible in court, it must be relevant to the issues at hand, accurately represent the facts it illustrates, and be helpful to the jury’s understanding
• It does not prove the facts themselves, but rather helps explain or illustrate other admissible evidence

 

For more, stay tuned to Evidence Room for upcoming in-depth classes and presentations by Scott Roder.

Scott founded the Evidence Room in 2001 — since then, he has consulted on over 1,500 cases in the United States and internationally. Scott has qualified as an expert in forensic evidence analysis, shooting and crime scene reconstruction, forensic animation, forensic photography, evidence collection and video analysis in federal and multiple state courts.