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FBI Laboratory seal

FBI Laboratory heading

Graphic for Structural Design Unit


The Structural Design Unit is responsible for the planning, design, and development of demonstrative evidence to support expert testimony during trial. Three-dimensional scale models, exhibits, and displays are created to reconstruct crime scenes and clarify to the jury the location and spatial relationships of evidence, witnesses, victims, perpetrators, and building structures.

Physical scale models may represent modes of transportation, such as vehicles used in a "chop shop" operation or trains, boats, and aircraft that were part of a crime scene. Building structures and terrain where crimes were committed are developed from onsite measurements, aerial photography, maps, photographs, witness interviews, CAD (computer-aided design) files, and blueprints. Bomb devices are replicated from remnants of crime scene evidence to depict the explosive housing, wiring configuration, and detonation mechanisms of these devices. Mannequins are also created to illustrate the findings of medical examiners with regard to the location of wounds inflicted on a body.

Scale surveillance models are also created to aid state and federal law enforcement personnel in the extrication of hostages during crisis response scenarios. These three-dimensional models provide realistic and accurate depictions of building layouts, including elevations, entryways, stairs, and obstructions. This ensures that crisis response planning strategies are based on the most detailed information possible.

The Unit also prepares exhibit displays that describe how law enforcement initiatives are developed to promote good relations and understanding between domestic and foreign law enforcement. These exhibits support special event ceremonies, such as joint leadership programs at international law enforcement conferences.

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Graphic showing a scale model of the Unabomber cabin

Scale model of the cabin used by the Unabomber in Montana

Graphic showing the interior view of the Unabomber cabin

Interior view of the Unabomber cabin showing the location of evidence

Graphic showing a scale model of the OKBOMB crime scene

Graphic showing a scale model of the OKBOMB crime scene and blast damage

Scale model of the Murrah Federal Building in Oklahoma City showing preblast (top) and postblast (bottom) views

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Information revised October 2000