Tuesday, March 30, 2010

Documenting the Crime Scene with A Sketch


by Andrea Campbell

After the first responder cordons off and protects a crime scene, the next step is a documentation of record that lays out the room and the evidence. Reports can be made in many different manners; for example, an investigator can record audio of the scene, take extensive notes, shoot photos or video, and map out the scene. 

Today we are going to talk about sketching.

Investigators need to document all observations of the scene. A sketch will help them to recall locale and evidence. They may make a rather informal first sketch, using any drawing tools, such as pencils, pens, even colored pencils. It probably won’t help to use chalk or charcoal because they smudge unless preserved with a setting spray. This is not a good idea at the scene, since other elements may be sprayed there.

Sketch after the scene has been photographed. This ensures nothing has been moved, kicked or otherwise disturbed. While a “rough” sketch will be difficult for some budding artists, rough is all you need in the beginning. If it's used in a court of law, it can be cleaned up. So go with messy and crude but accurate.

Sketches help clarify what is where in a photograph. A sketch may offer a different perspective, such as a top-down bird's-eye view, an elevation or side view, or a three-dimensional view. Oftentimes an exploded or larger view can accompany any perspective; this view may be a close-up or cross-sectional view of the scene.

What should you document? The physical artifacts, such as furniture, tables, lamps, and so forth, similar to a blueprint; the precise location of weapons, evidence, and the body; even a traffic pattern. Investigators may use this documentation to help with interviews, jog someone’s memory, establish a permanent record of the scene or location, and assist when writing a report. In jury trials, sketches can help answer various questions and aid witnesses, lawyers and judges. If the perpetrator or suspect visited several areas of the house, for example, going from bedroom to bathroom or into the kitchen, the sketch will help to recreate the series of events. With accident scenes, sketches may display distances for a better understanding of the sequence of events. 

*Note: Don’t forget to reference on your crime scene drawing where you were standing.

A final sketch can be made using templates or a computer. It should indicate distances; most art uses a scale of one inch to one foot to ease understanding. The sketch needs a label of the crime, such as Private Residence and Homicide. It needs the name of victim,  location, date and time, case number assigned, and the initials or name of the person who drew it. As with any good map, include a legend so the reader can learn some facts without having to ask. Besides the scale, indicate direction if possible -- north, south, east, west. Try to indicate which way doors open, potentially important elements later on. If you use symbols to represent something, such as a square for a seat or a triangle for an end table, make that known. You may code key elements with the alphabet for clarity. Itemize specific evidence, artifacts and elements. The couch might be where the body was found, making it item “A” or, in a numbered system, “1”. Don’t include clutter that's not relevant. A pile of clothes may not mean anything -- unless it has blood on it. Label a table of measurements with the disclaimer “All measurements are approximate.”

Remember that a bird’s-eye view won’t show the height of items at the scene. If the gun was on top of a cabinet, only an elevation view with measurements will indicate that. A 3-D crime scene is usually the function of a computer rendering, created by a software program.

If the distance markers were established or made by someone else, make note of that for credibility. It's better to anticipate a question than try to answer one if you get blindsided in court.

The National Crime and Investigation Training website has an example of a sketch. See: http://www.ncit.com/Tips Tricks/Sketching/sketching.html

The Crime Scene Sketch has a pdf file of key facts to remember along with tips. (Search Crime Scene Sketch):
http://www.bcps.org/offices/science/secondary/forensic/Crimescene%20Sketch.pdf

Another extremely detailed pdf file, complete with CAD drawing examples and notes on triangulation of measurements, can be picked up here:

One particularly delightful website, created by retired forensic investigator Thomas F. Hanratty, includes crime scene sketches from all Sherlock Holmes cases.

An absolutely beautiful rendition, including some top-notch software examples, can be found at: http://www.doj.state.wi.us/dles/crimelabs/physicalEvidenceHB/Ch4_CrimeSceneSketch.pdf

A commercial site that sells the Smart Draw program: http://www.smartdraw.com/resources/how-to/Crime-Scene-Diagrams

1 comment:

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