Using iWitness to map a staged crime scene with the Nampa, Idaho Police Department


In cooperation with the Nampa, Idaho Police Department during the DCS iWitness photogrammetry training workshop, a staged homicide scene was mapped using a Nikon D200 digital camera. The staged crime scene was setup in one of the training rooms frequently used during Nampa police training exercises. A mannequin (simulated murder victim) was placed on the bed, partially under the bed covers. A simulated blood stain was present on the pillow.


The goal of the mapping exercise was to produce an accurate 3D model of the contents of the room with the digital camera and iWitness. At the request of one of the officers in training, four of the Reference Point Markers were placed on the bed, simply to assist as common tie points during the digital imaging in the room.


Approximately 50 orange 'sticky dots' were randomly placed on the walls and other objects in the room, to facilitate common shared points so that the enter project could be complete in one iWitness network of 3D measured entities.


3D points, line and poylines measured in iWitness


Thirty three camera stations were used to map a little over two-hundred 3D points, of which were mostly natural features, being a combination of points, lines and polylines in iWitness. The on scene time was about 30 minutes to capture the images.


The 3D accuracy once measured in iWitness was one-tenth of an inch (2.5mm) RMS. The results of the iWitness measured entities were exported as a DXF file and imported into the CAD Zones Crash Zone diagramming software. On a laptop computer, it took an experienced operator about 5 hours to measure the 33 digital images to produce the 3D points (a process now that is optionally available and automatically complete in 5 to 10 minutes using iWitnessPRO and accurate to fractions of an inch.)


iWitness measured all of the features required to "diagram" the scene. Approximately 70 digital images were acquired, and more detail in the scene can be accomplished at anytime in the future (if this was in fact a real-world incident where it was critical to map more features.)


To review a PDF (600KB file size) of the complete bedroom mapping project, using iWitness, click here to download.


Back to top