Do CSIs Really Use Chalk Outlines?
This question has come up from some readers so I’m going to address when CSI’s might mark the position of bodies or other evidence. 99% of the time we do not use chalk (or something similar) to trace an outline of a dead body. Actually, I’m not entirely sure if this was ever a common practice or if it was just a product of television and film. I’ve reviewed a lot of historical crime scene photos and I’ve rarely seen any type of marking, let alone a full outline. Before the advent of insta-matic (Polaroid) or digital cameras I can imagine an investigator marking a body position before it was moved so he could keep that “perspective” while investigating the scene.
CSIs certainly take measurements to various points of the body (hands, feet, head, elbow, etc) so the body can be properly scaled and drawn into a crime scene sketch. Typically this is all that’s needed. If, however, the CSI plans to remove the carpeting to be used later for a reconstruction or in court then they may decide to mark the location of those measurement points with something like a black sharpie marker. You wouldn’t trace the entire body but you might mark the location of the hands, feet, or head as well as any relevant objects. This can be very helpful if the room contains little or no furniture that can be used as a point of reference in the crime scene photographs.
In such cases, if the position of these items are marked then there is less risk of losing the proper perspective months or years later when re-creating the room for the courts. Defense attorneys will also have a harder time arguing that your reconstruction is not putting the victim back into the proper position. Of course, before we do anything like this around a dead body we would need to consult with the Coroner or Medical Examiner (at least in the United States).
If the body is located outdoors in a publicly accessible location, we may need to move the body before sophisticated measuring devices (like a total station) can be brought in. Unlike an interior room you may not have any fixed point (like a wall) that is close by in a large open field. Under these circumstances the CSI might mark the main body locations with pin flags or other markers that can be mapped in later when the total station can be set up. But these conditions aren’t very common and CSIs take a lot of photographs in most cases. I have used spray paint to mark the locations of vehicle tires at the scene of an accident so that the vehicles could be moved but obviously I would never spray paint a body!
So when describing your crime scene you’d be better off leaving the chalk in the classroom.