Documenting a Crime Scene

Conventional forensic surveys of crime or accident scenes — known as “total station work” — involve photographing the scene from numerous angles with a standard camera, tape measuring distances between critical objects, and diagramming relative positions of pieces of evidence. This survey technique has two fundamental weaknesses: time sensitivity and point-of-view.

First, crime and accident scenes are time sensitive and can be corrupted in a matter of minutes. Second, a forensic team generally approaches a scene with a theory of what took place, and if they are wrong, it may be impossible to go back to the scene for a second try. Pine Falls Technical Services — a metrology consulting firm — showed the Royal Canadian Mounted Police (RCMP) and the Winnipeg Police Department, how a laser-based imaging device could piece together the remains of a vehicle that had been destroyed by a bomb. A pipe bomb was placed under the front seat of a large station wagon. What police saw was a blast that scattered parts of the car around the pit, but left a major piece of it intact. The training demonstration gave Pine Falls’ engineers a chance to apply new technology to what has been an age-old problem of forensic surveys.

The FARO Laser Scanner is the latest in a new generation of metrology tools. Essentially, the device is a 3D camera that employs a laser as a light source, capturing the reflected image in extreme detail. A scene sweep can be 360°x 320° with a range as far as 76 meters. It captures 120,000 points per second – up to 100 times faster than most time-of-flight scanners. In forensics, a primary benefit is the fidelity and permanence of the images, plus the ability to view the image from any angle.

The test at Winnipeg showed that gathering crime scene data can now be simple and fast, quickly freeing up the area for civilian use. The destroyed car and scattered parts were digitally captured all around the gravel pit, giving a comprehensive view of what happened in the explosion. “We knew how fast the FARO Laser Scanner worked and the extreme detail of the images that it produced,” explained Doug Ursel of Pine Falls Technical Services. “It seemed like a natural fit for reconstructing crime or accident scenes.”

Learn more about the FARO Laser Scanner Photon.