Keen to learn about one of the most valuable (moving) sources of forensic evidence? You might just be driving it. Motor vehicles (the fancier phrase for anything on wheels, sanctioned to drive on roadways) serve as time capsules that store fibres, glass and other types of trace evidence. They also happen to be commonly overlooked by persons committing a crime — as we tend to think of communal areas (living rooms, bedrooms or bathrooms) as being immobile.
Pedal to the metal, and go
In actual fact, more forensic laboratories are investing in larger forensic garages: tricked-out facilities that are dedicated to processing evidence from vehicles. In the recent past, such examinations actually occurred in parking structures or lots for impound vehicles. The downside was that it wasn’t a controlled environment in which to conduct specialised forensic testing; and it wasn’t all that secure: suspects were oft-known to climb into the lots, over the surrounding walls, and steal their vehicles from the tow yard.
Just what does vehicle processing look like these days, and what does this type of analysis involve? Read on, as we bring you a little closer to the forensic garage as it exists now. We’ll be focusing on searching the vehicle (as there are a number of other approaches you can take to processing, depending on the nature of the crime or accident).
1. Getting to the carburetor of things: interior searching.
First things first: all investigators need to be on the same page, so common reference points need to be established.
To do this, the interior of the vehicle is divided into sections (we’re obviously talking about cars here, as demonstrating the process is probably most simple that way). The back of the driver’s seat might be labelled “B” for instance, and the floor driver side is “C.” An infrequently utilised approach is to divide the car into separate quadrants according to the seat in question with further sub-numbering for any additional features found within the grid.
Sketches and photographs are taken to corroborate stories: how were people sitting in the motor vehicle? Who was the driver and which passengers were sitting in the backseat? Stock is taken of any additional items found — investigators are always on the look-out for any medications or controlled substances that may have impaired the driver; or changed the atmosphere within the vehicle.
Once extraneous, larger items have been properly documented and in some cases removed; trace evidence is collected from the seats, the floors and the windows. These samples are sent to the relevant forensic laboratories (e.g. blood-stained carpet pieces are sent to biological examination facilities).
2. How’s that paint job? Looking at the exterior.
The outside examination begins in much the same way: everything is labelled. After this, common protocol is to collect questionable traces of paint samples from the vehicle (normally anything that’s alien to the actual car you’re looking at is a bit strange and should be studied in more depth). Any areas of damage are assessed, and around the scene (assuming you might still be there) any debris associated with the scenario are collected.
Often, material torn off or left behind on the roadway can be tremendously important: clothes from a hit-and-run accident victim, for instance, might be key to reconstructing the accident; and to determine the sequence of events.
Your Turn: Ever had your motor vehicle impounded for forensic analysis? Care to tell us why? Share your stories (especially if you’ve helped conduct one of these examinations). We’d love to hear from you.