Crime investigators depend on different sources of evidence to identify the suspect or unravel how an incident occurred. One of the significant sources of evidence is paint, especially in hit-and-run cases since it can help to link the victim and the suspected automobile. Paint can provide treasured evidence in numerous other crimes, such as homicide and robbery (Saferstein & Roy, 2020). Additionally, soil contains uncommon features such as fragments, fossils, or debris that can be adequately varied and inimitable, making it valuable in customizing a sample and being an excellent source of forensic evidence. The following sections of the paper address ways of collecting and preserving paint and soil evidence and their handling for proper forensic laboratory examination.
Proper Collection and Preservation of Paint Evidence from an Automobile
Before collecting and preserving paint evidence begins, the investigator must first secure the crime scene. The investigator should also take pictures of the crime area without unsettling the evidence. Afterwards, the collection of the paint evidence begins by cautiously scraping or peeling the paint using tools such as tweezers (Saferstein & Roy, 2020). The collected paint evidence should be the same color and type found on the suspicious vehicle. Paint rubbles should be collected in a paper sachet and placed in an envelope.
In most hit-and-run cases, paint from the vehicle is mainly in microscopic quantities. The investigator can collect the automobile if the sample is tiny or cannot be detached to avoid losing the evidence. The victim’s garment should be handled well and placed in a separate paper bag for delivery to the crime laboratory. If the car has more than one color, only that part of the color area which hit the victim is collected and transferred. The collected paint evidence can be handled using glass vials and metal or cardboard boxes for protection from breakage and damage. The investigator should clearly label the containers with the date, time of collection, the collector’s name, the specific source and the location of the sample.
Proper Submission of Paint Transfers and Paint Standards from Motor Vehicles for Laboratory Examination
When submitting the paint evidence to the laboratory for examination, the investigator must clearly label the container with the item number, agency case number, and an appropriate brief description. Kumar (2018) indicates that the container should be tape sealed, and the initial and date indicated. The evidence is then submitted to the laboratory and completed documentation, including a case summary or report. Numerous bodies have developed different standards to guide the collection and submission of paint evidence for laboratory examination, including the FBI Laboratory’s Handbook of Forensic Services, CFS Evidence Submission Guidelines, and the BFS under the California Department of Justice.
Soil Evidence Collection and Preservation in a Criminal Investigation
Collecting soil evidence begins by ensuring impressions in the soil, such as tire tread patterns or footprints, by taking photographs. A scale and a plaster cast are created before the footprint is disturbed. Soil firmly attached to some object, such as a shoe, should not be removed; instead, the whole item is collected (Kaur et al., 2020). The soil is dried by air then the object is carefully wrapped in butcher paper and placed into a paper bag or other suitable vessel. If the soil is loose, it can be swept onto a clean piece of paper and folded to contain the sample.
The investigator should carefully preserve the soil sample to uphold the integrity of soil evidence. Once the sample is collected, the investigator should submit the soil evidence to the forensics laboratory in a state that satisfactorily characterizes its original state. Handling of the soil evidence must be minimized and protected from harmful or mechanical changes, corruption, and unintended loss. The sample packages should be wrapped correctly using tamper-evident means to maintain the chain of preservation.
Crime Lab Forensic Soil Examination
The crime lab seeks to use soil evidence to profile the chemistry of the soil to show a probable origin. The process begins by drying the collected soil sample to avert further material decomposition. Afterwards, the forensic soil experts conduct physical and chemical tests to compare soil samples found on the suspect and the crime scene. The initial analysis is conducted through a microscope to identify whether there are similarities in soil particles or not. Kaur et al. (2020) state that if there are similarities, simple and rapid screening approaches are applied for color comparison and to study the distribution of particle sizes. Instrumental analysis is then conducted, especially by using scanning electron microscopes (SEMs)and transmission electron microscopes (TEMs) to study the chemical composition and morphology of the particles. Inorganic elements in the soil sample are examined through elemental analysis. At the same time, ground-penetrating radar (GPR) technology is applied to detect variances in the soil by finding breaks in the soil structure. An additional examination can be conducted on soil and soil classification, remote sensing, terrain analysis, and geophysics.
Handling evidence at the crime scene is critical as it influences evidence collection, preservation, and submission. Before collecting evidence, the crime scene needs to be secured to avoid contamination and pictures taken. The collection and preservation of evidence are based on the material being considered, either paint or soil evidence. Different tools are used to collect and preserve the evidence. The evidence is then properly submitted to the laboratory for examination, where specific standards and guidelines are observed.
Kaur, J., Sodhi, G., & Singh, G. (2020). Forensic important of soil evidence: A review. Review Article International Journal of Forensic Science, 3(1), 43–49. Web.
Kumar, A. (2018). Exchange of paint in hit & run collisions and its significance as forensic evidence. Journal of Forensic Sciences & Criminal Investigation, 8(1).
Saferstein, R., & Roy, T. (2020). Criminalistics: An introduction to forensic science (13th ed.). Pearson Education (US).