I still have Will and RJ out at the crime scene in my novel, Against Flesh and Blood. Here’s some of the things done up to this point:
- They’ve identified the location where the crime scene occurred.
- They’ve noted three different sets of footprints. They placed ID tags next to a representative sample of each. There’s the footprints of two girls and one guy. Since the footprints are different, they’re able to untangle which is which and ID the footprints of the girl who got away, the one who fell and was caught, and the perp.
- The tire tracks made by the car.
- The location and breakdown of personal effects found tossed in the ditch alongside the road.
- Where the crime occurred.
From this, they can now begin to generate a sketch of the scene.
Note, not every case will have a crime scene sketch made. Some contain very little worth sketching, or the case is too small to warrant one. That said, I’ve always made one when possible, if for nothing else than to help me recall how things were laid out.
Back in the day, we did sketches the old fashioned way. We sketched it using graph paper, a ruler, and a pencil. There were plastic templates available that allowed us to sketch in bodies, body part, guns, some furniture, etc. We couldn’t afford them so we did the best we could.
The first thing to think about when doing a sketch is that there’s no way it will be to scale. Again, you’ll be doing the best you can.
One of the things you might want to do is identify several “fixed” points to get your measurements from. You don’t have to do measurements, but the more serious the case, the more likely you’ll want to get them.
If you’re inside a square room, you’re in luck because the walls and corners probably aren’t going to go anywhere. That said, you want to establish the length of each wall and how the connect (in most cases this will be 90 degree angle). We want to identify features in the room (door, window, closets, etc.).
The square room is a natural grid for you. It becomes a little like plotting points on a graph. For instance, I notice a knife lying on the floor. I can measure up along the wall till I’m 90 degrees from the knife. I put that distance from the corner to that point. I then measure from that point to the knife. That gives me the location where the knife was lying from that wall. I do it from the wall that runs 90 degrees from the first wall, and do the same thing. Now I can place the knife in two dimensions. Usually, that might be good enough, but if I want to be 100 percent sure, I can add a third, maybe even a forth measurement and place it exactly.
One of the reasons I’d do that is so if something did happen to that room (think building burns down). I can still map out a square in an area, and using the same measurements show where things were located.
You can do the same thing with an external location, but there’s challenges involved.
First, you need your fixed points. The best fixed points, again, are things that aren’t going away. An example might be the corner of a building, a light pole, or such. In RJ and Will’s
case, they use three power poles. These are fixed objects, and even if the utility company replaces one, they know where the old one was. Power poles have an ID number of them, and they make great markers.
Fence posts aren’t so perfect. Fences fall down, they’re dug up and replaced, and there you are. Only once did I ever use a fence post and that’s because I had no choice. I still did it in a way that I could lay out a baseline using the fence, and took my measurements from points along that line (marked by a post). I knew the distance between my two points and took my measurements from there. The idea was where lines a certain point from those fence posts would intersect, and that was my evidence. I didn’t like it, but there was little I could do about it.
In my hero’s case, they have their fixed points and they treat the scene like a grid chart, and are able to generate their sketch and measurements.
One might be tempted to use GPS to map out a crime scene. While GPS is very precise, you still need to know where things were in relation to other things. Measuring is very precise, and while GPS might be good enough to get you within a few feet, maybe even inches, it might not be good enough.
Today, crime scene sketches can be easily generated on a computer. There’s tons of software out there that will help you out so you can produce professional sketches.
Smartdraw makes a really nice product that produces so first rate sketches.
This Link will give you instructions on how to generate a sketch using MS. Word (Never tried it – and I don’t know how well it works). Just an FYI, it’s a little dated.