Crime scene sketching

Crime Scene Sketching The effect of modern media on crime scene investigation has led most people to believe that crimes are relatively easy to solve and may only take a day or two to complete. In actuality crime scene investigation is a lengthy process in which investigators can spend years investigating one crime. The components of crime scene investigation themselves can be rigorous and demanding depending on the circumstance.

A vital piece of crime scene investigation is crime scene sketching; a tool that seems to be less in the forefront of modern television shows, perhaps because this is a less effective way to portray the gore that attracts the audience to most of these shows in comparison to crime scene photography that is often highlighted in shows like CSI. Crime scene sketching however is a critical part of crime scene investigation.

Crime scene sketching in comparison to crime scene photography can capture a “ bird’s eye” view of the crime scene, can show relativity between items and can offer a “ whole crime scene picture” instead of being in fragmented pieces or from one particular angle like photographs. Crime scene sketching has been a long standing process in investigations and is a technique that has an abundance of benefits. It is a permanent record that provides supplemental information that is not easily accomplished with the exclusive use of crime scene photographs and notes.

A crime scene sketch depicts the overall layout of a location and the relationship of evidentiary items to the surroundings. It can show the path a suspect or victim took and the distances involved. It can be used when questioning suspects and witnesses. During trial, the crime scene diagram correlates the testimony of witnesses and serves as a tool for relaying reference and orientation points to the prosecutor, judge and jury. A crime scene sketch is a rough drawing/scale model drawing composed by an investigating officer at the crime scene.

The crime scene sketch is a simple line drawing that indicates the position of the body in relation to fixed and significant items in the scene (ex: a door, table or window)(Garrett). It is usually in addition to an officer’s written report and photographs. The crime scene sketch is an amazing visual aid, and because officers can choose which items to include in the sketch it can eliminate unnecessary items that photographs can’t like clutter or items that are unrelated, it also can highlight the significance of important items like the closeness between the victim and the murder weapon or unusual blood spatter. DOJ Wisconsin) It has been well established in court that a well drawn diagram is an aid to the judge, jury and witnesses in visualizing the crime scene. Their admissibility usually lies in their relevance and accuracy. This type of evidence may be referred to as illustrative or demonstrative evidence. (DOJ Wisconsin) Even poorly drawn sketches have been admitted into evidence, as long as they are shown to be fair representations of the scene and it’s surroundings. There are four types of crime scene sketches used in investigations; Overview sketches consist of a bird’s-eye-view or floor plan sketch of the scene.

This is the most common type of sketch and consists of items on the horizontal plane. An elevation sketch portrays a vertical plane rather than a horizontal plane. Examples include bloodstain patterns on vertical surfaces such as walls or cabinetry and bullet holes through windows. Exploded view or cross-projection sketches consist of a combination of the first two sketches. It is similar to a floor plan except the walls have been laid out flat and objects on them have been shown in their relative positions.

Perspective sketches depict the scene or item of interest in three dimensions. It is the most difficult sketch to create and requires some artistic skill. (Gerber, 216) When an investigating officer begins his sketch he must have paper (typically graph paper to include proper measurements to scale, but blank paper is often used), a pencil and eraser, a ruler or straight edge and a steel tape usually 100’ ft. It is also extremely beneficial to have a compass to determine true North.

Measurements are an important part of the crime scene sketch, something that photographs cannot do. In photographs angles can make objects appear closer or further apart than they are in actuality. Drawing things to scale is not always necessary, although it is valuable to do so. Drawing sketches to scale avoids a distorted view of the scene; measurements must be reduced in proportion so that they bear correct relationship to each other; however, in drawing sketches not to scale Sketch can be accomplished more quickly than a scaled diagram.

Items are placed in the diagram based on approximation by the investigator drawing the scene. This type of diagram may provide a distorted view of the scene. Correct proportions and relationships between objects may not be maintained. Measurements are recorded on the sketch or in a chart. This rough sketch may be used to complete a scaled diagram later. These diagrams should be clearly marked as not to scale. (Garrett) All measurements are taken from a fixed point, a door or window, stairs or a chimney. They should be exact and taken with a steel tape or ruler.

Usually one investigator takes the sketch while another officer takes measurements and while investigators can often estimate relative distances or positions in rough sketches; measurements are taken for exact locations. In situations where no measurement instruments are available investigators can use pace measurements but these are not exact and are often less reliable and credible. (Hess and Orthmann) A crime scene drawing is one of the simplest and most effective ways to show measurements, these measurements are important because they show relativity and distance between significant items.

The investigator has five ways to show these measurements in a crime scene drawing. These measurement techniques include: Straight-line in which two measurements are made, one from each side of the object, to a fixed point in the diagram. This method is usually used to mark positions of furniture or evidence against a wall like blood spatter. The second method an investigator can use is the rectangular coordinates or perpendicular distance method in which two measurements are taken at right angles of an item to the nearest two permanent objects, often walls.

This method is usually the best way to mark the location of a body or other significant evidence. The polar coordinates or triangulation method is done by using a compass and a protractor, the investigator locates two fixed points and transfers this information to the sketch. Measurements are then taken from these two fixed points to the object, forming a triangle, where these two points intersect is the exact location of the object. The fourth method used for finding measurements is the base line method; this method is used for a scene that doesn’t have a straight perimeter like a large wooded area or a river.

In the baseline method a straight line is drawn through the scene and each end is located and measured. A starting point is designated (ex: the north side of the river is determined the starting point) and the base line is then used as a reference for all of the other measurements. The final technique for measurements is the two fixed point method where an investigator takes two straight line measurements to two fixed points within the scene. In this method no right angle is required, but the two points used should not be close together.

In a professional and legally correct crime scene sketch an officer will include a title block, this title block includes: the name and title of the investigator who drew the sketch, the date and time that the sketch was made, the classification of the crime (homicide, burglary etc. ), the identification of the victim if known, the agency’s case number, any names of persons assisting in taking measurements, the location of the location sketched, and the reference points included in the legend such as compass directions.

Several CAD based programs are commercially available that can be used to create a professional and accurate crime scene diagram. With laptops becoming more common, these types of programs can be used at the scene to record measurements and generate sketches. These diagrams can also be generated back at the office using rough sketch(es) created at the scene. Portable devices now exist that can perform a 360° scan of a crime scene in as little as 20 minutes, capturing millions of measurements of all objects visible to the scanner. Dozens of high-resolution images are captured automatically.

The device requires only the space needed by a standard photographer’s tripod. The data generated can be used to find the distance between any two points in the scene, to view the scene from any vantage point (including directly overhead), and to create a full-color, 3D model for investigative and courtroom purposes. (DOJ Wisconsin) With the benefits of crime scene sketching and the advancement oftechnology, crime scene sketching is more than ever being helpful in investigations and court. The benefit of crime scene sketching will continue to develop as more ways of crime scene sketching becomes available.