3D Laser Scanners Are Bringing Horrifying Crime Scenes to Life

To help investigators and jurors scour for evidence at their leisure, police forces in the UK are increasing the use of laser scanners able to capture bloody and ravaged crime scenes and transform them into extremely detailed 3D models.

I encountered one of these scanners yesterday during a demonstration at one of the many events taking place as part of London Technology Week. The scanner, produced by a US-based company called Faro, looked like a blue box split in half with a small revolving mirror in the middle. It was mounted on a tripod, and manned by an amiable engineer named Simon Horton.

Horton asked everybody in the room to stay still while the blue box started rotating, and the spinning mirror 3D-scanned everything around it, including the audience.

The outcome was somewhat unflattering: my 3D doppelganger had a sullen and ghastly air, while the 3D rendition of my two-day stubble looked like a full hipster beard. That was probably partly due to the fact that the demonstrative scanning had been made hastily, at a relatively low resolution, and in black and white. Had the room been a real crime scene, the audience’s 3D model would have been no doubt more colourful and less spectral.

3D laser scanners like Faro's (or its hand-held competitor Zebedee) were originally developed for engineering purposes—such as checking measures and dimensions of mechanical components—but are increasingly becoming part of the police toolbox all over the UK and elsewhere.

In a few minutes—about five minutes per scan, with each location requiring a different number of scans depending on its shape—these devices can create very accurate three-dimensional maps of any crime scene, carrying out the kind of reconnaissance that so far has been done by spending hours shooting tens of pictures and taking the necessary measures with wheels and tapes.

And it's not just violent crime scenes: the precision of the measurements recorded by the scanners comes in quite handy in investigations of traffic accidents, when even a difference of a millimetre can be crucial to tell who is to blame for the crash.

But more than time efficiency and computational accuracy, forensics teams in many countries are using these scanners for the sake of vividness.

First of all, scanners provide a 360-degree record of everything present on the crime scene when it was explored, and while photographic evidence is selective—that is, you have to spot something to take a picture of it—scanning is all-encompassing. If something was there, it will appear on your screen later, proponents argue.

That’s why, as Horton told me, scanners can save a cop’s day, “if he has overlooked anything like a bullet hole, or a blood spatter, or a weapon left on the crime scene.”

Later in police proceedings, 3D crime scene models can help judges and jurors hearing a case to fully grasp what the setting where some heinous act has (or hasn’t) taken place looked like when the police first walked there. Should adoption continue to rise, that's bound to change the way in which courts visualize and immerse themselves in the reality of the cases they’re called to rule on.