Abstract:

A crime scene investigation is a process of preserving, processing, and reconstructing a crime. It makes no difference where the crime occurred or whether there were many crime sites involved. The process of conducting a crime scene investigation entail identifying, gathering, and analyzing evidence that was discovered there. The whole process of acquiring evidence requires that crime scenes be properly documented. Crime scene sketching is a critical aspect of the investigation process, as it provides a visual representation of the scene that can be used to support the investigation, analyze and interpret evidence, and communicate findings. The sketch is created to depict the items, their positions, and their connections. It need not be a scaled architectural drawing, but it must include precise measurements where necessary. A sketch has the benefit of being able to cover a vast area. There are generally two types of crime scene sketches- rough and final sketch. Rough sketches are created during the crime scene assessment/preliminary scene evaluation phase to aid in the creation of a processing strategy. On the other hand, the finalized version of the rough sketch is known as a final sketch. There are several different techniques and methods used in crime scene sketching such as orthographic sketches, cross-projection sketches, polar coordinate method, triangulation method, etc. In the past few years, new technology has taken over and made it easier for crime scene investigators to reconstruct crime scenes with great precision. Crime scene sketching is an important aspect of the investigation process that provides a visual representation of the scene for use in analysis, interpretation, and communication.

A crime scene investigation is a process of preserving, processing, and reconstructing a crime. It makes no difference where the crime occurred or whether there were many crime sites involved. A victim who was killed in one place and discovered in another can have more than one site included in a crime scene. A crime scene can be on the land, in the sea, in a tree, or six feet beneath the surface. The process of conducting a crime scene investigation entail identifying, gathering, and analyzing evidence that was discovered there. To accomplish this, forensic science professionals or experts are required. When conducting investigations, forensic science interprets the evidence using scientific procedures or techniques. Often, a specialized team of forensic technicians attends a crime scene to collect, record, and properly preserve evidence like blood, fingerprints, etc. To help ascertain precisely what occurred at the time of the crime, the obtained evidence is next scrutinized and analyzed. The whole process of acquiring evidence requires that crime scenes be properly documented. Extensive notes and observations should be made while taking pictures and measurements, and they will be referenced innumerable times throughout an investigation. Because most crime scenes are not permanent, it is crucial to thoroughly and accurately document every detail before the victim is taken away. This is because the scene cannot be recreated exactly as it was when the first law enforcement personnel arrived at the scene and cannot be restored to its original state. As soon as authorities arrive, the crime scene must be preserved in order to preserve its integrity for processing and collecting evidence.

Crime scene sketching is a critical aspect of the investigation process, as it provides a visual representation of the scene that can be used to support the investigation, analyze and interpret evidence, and communicate findings. A scale drawing that places the evidence in relation to other things is a crime scene sketch. Reports and photos are utilized alongside sketches to document the scene. Simply put, a crime scene sketch is a drawing that depicts a crime scene as it actually was. The sketch is created to depict the items, their positions, and their connections. It need not be a scaled architectural drawing, but it must include precise measurements where necessary. A sketch has the benefit of being able to cover a vast area. The crime scene sketch is an addition to the scene's captured photographs and recordings, the investigator will sketch the crime scene after taking photos. Providing a realistic representation of the crime scene is the crime scene sketch's goal rather than producing an artistic image. Therefore, the majority of law enforcement personnel are able to sketch a crime scene. It can reveal the routes taken by a suspect or victim as well as the associated distances. It can be adopted while interrogating witnesses and suspects. The crime scene diagram is a tool used by the prosecutor, judge, and jury during a trial to communicate reference and orientation points and to connect witness testimony. A thorough understanding of the scene should be obtained before beginning a sketch. Establish the sketch's boundaries and select what to include and eliminate. For sufficient documentation, several sketches may be required if the scene is complex.

There are generally two types of crime scene sketches- rough and final sketch. Rough sketches are created during the crime scene assessment/preliminary scene evaluation phase to aid in the creation of a processing strategy (fig, 1). The sketch is very crude artistically, not done to scale, and can be created with any tool (crayon, chalk, pencil, pen, etc.). The drawing will be updated as work at the crime scene advances to add measurements of objects and structures as well as the distances between them. It will also include a rough layout of the crime scene. On graph paper with so many squares representing so many square feet or inches, a rough sketch is typically done initially on the spot. The distances between objects and/or structures at the crime scene are measured using a tape measure or other measuring tools. The original rough sketch ought to be saved and kept in good condition in case it becomes necessary at a later time. On the rough sketch, these measurements are proportionately lowered, and the items are added. In order to position the objects in a sketch where they belong, two measurements taken at right angles to each other or from two reference points are typically sufficient. To ensure accuracy, additional measurements should be conducted. This is particularly valid when calculations will be applied later.

Fig. 1 Rough Crime Scene Sketch (Sirchie Fingerprint Laboratories)

On the other hand, the finalized version of the rough sketch is known as a final sketch (fig. 2). They frequently do not display all measures and distances initially noted on the basic sketch because they are typically prepared for courtroom presentation. In a final sketch, only important elements and structures are usually visible. A final sketch is created in an unchangeable format (not in pencil), either in ink or on a computer. The sketch must be clutter-free and precisely represent all relevant pieces of evidence, usually with the use of an auxiliary legend. A legend is a note of explanation that is located outside of the sketch area and refers to a particular object, symbol, or piece of information that is shown graphically in a sketch.

Fig. 2 Final Crime Scene Sketch (Sirchie Fingerprint Laboratories)

There are several different techniques used in crime scene sketching, each of which has its own strengths and limitations. Orthographic sketches are two-dimensional drawings that provide a bird's eye view of the crime scene (fig. 3). These sketches are useful for showing the spatial relationships between objects within the scene, and they can be used to highlight important features or evidence. However, they are limited in their ability to convey a sense of depth and volume.

Fig. 3 Orthographic Crime Scene Sketch (Physical Evidence Handbook, 2017)

Isometric sketches are three-dimensional drawings that provide a more detailed view of the crime scene. They can help to demonstrate the relationships between objects in the scene and to illustrate the positions of evidence. However, they can be time-consuming to create and may not always be necessary, depending on the nature of the crime scene. Elevation sketches use views from the front and the side, it is a technique for accurately capturing a crime scene (fig. 4).

Instead of depicting a horizontal plane, it shows a vertical one.

A Cross-Projection sketch resembles a floor plan except that the walls are flat and the objects on them are displayed in relation to one another (fig. 5). In this sketch, the walls are folded down to reduce the three dimensions to two. Any evidence that can be discovered on walls, including windows, photographs, blood splatter, and other objects, can be flattened to help explain relationships. Compared to an elevation sketch, which preserves the walls and relies on illustrating the three dimensions of the evidence, it is simpler to create.

Fig. 5 Cross-Projection Crime Scene Sketch (Physical Evidence Handbook, 2017)

There are majorly three different methods used for sketching a crime scene- polar coordinate, transecting baseline coordinate and triangulation method. When there is only one fixed or reference point in an outdoor scene, the Polar Coordinate method is preferred. Measure the distance and angle (direction) of an object in relation to a predetermined reference point (fig. 6). A big protractor or an optical tool like a transit or compass can be used to measure the angle. Underwater images benefit from the protractor approach using a 360-degree protractor. When there are many artefacts at the crime scene and conventional measuring methods are ineffective, the Transecting Baseline Coordinate method is employed to measure pieces of evidence (fig. 7). This is achieved by laying a tape measure across the whole room or area to be measured. All subsequent measures made at the crime scene are compared to this initial tape measure as the standard. A second tape measure is laid at a 90-degree angle to the first one, and measurements are then taken out to the evidence starting from this tape. The Triangulation Method uses fixed objects as measuring points and provides a bird's-eye view of the scene (fig. 8). This is especially helpful when sketching crime scenes outside when there aren't any obvious points of reference. Two or more far-spaced points of reference are needed for this process. A triangle is created by connecting the two reference points with a line and by drawing a line from each reference point to the object being measured. The ideal distance between the object being measured and both reference locations would be equal.

Fig. 6 Polar Coordinate Method

Fig. 7 Transecting Baseline Method

Fig. 8 Triangulation Method

In the past few years, crime scene sketching has been made easier through computer-based programs to help develop an accurate representation of the crime scene. Diagramming software is a powerful tool for crime scene sketching, as it allows investigators to create a virtual crime scene. These programs provide a more accurate representation of the scene and can be used to create animations or simulations of events. However, they require specialized training and may be expensive to use. Programs such as Visual Cadd, FARO Zone and SketchUp have made it easier for crime scene investigators to reconstruct a crime scene with precision (fig. 9).

Fig. 9 Crime Scene Reconstruction using FARO 2D Software.

Conclusion:

Crime scene sketching is an important aspect of the investigation process that provides a visual representation of the scene for use in analysis, interpretation, and communication. Regardless of the method used, it is important to ensure that crime scene sketches are as detailed and accurate as possible. This includes measuring distances, accurately placing objects, and including notes and annotations to provide context. Crime scene sketches are used in court proceedings and can be a critical piece of evidence, so it is essential to ensure that they are accurate and reliable. The new technology however is making the job easier for crime investigators all over the world, it makes the evidence more viable in court.

References:

1. FARO® Zone 2D Software | FARO. (n.d.). Faro. https://www.faro.com/en/Products/Software/FARO-Zone-2D

2. Investigations | Section 2.2. (2021, June 7). Professor McKee’s Things and Stuff.

https://www.docmckee.com/WP/oer/investigations/investigations-section-2-2/

3. Lama, S. (n.d.). Police Science and Law Enforcement. Pathshala. https://epgp.inflibnet.ac.in/epgpdata/uploads/epgp_content/S001608/P001746/M022163/

ET/1504500890et.pdf

4. Physical Evidence Handbook. (2017). https://www.newcastle.k12.ok.us/Downloads/crime-scene-sketch-2017.pdf

5. Tacoma Police Department. (2004). Crime Scene Diagramming. Forensic Services Policy and Procedure Manual. http://desksgt.com/Classes/Reading/Crime_Scene_Diagramming.pdf

6. Visual CADDTM Official Site. (n.d.). https://visualcadd.net

Written By:

Mayuri Bisht 

National Forensic Sciences University

Masters in criminology 

(esp. in Forensic Psychology) 

AFRS Intern (AFRS_IP2314)