DNA Evidence and Proper Organization of the Crime Scene Investigation
DNA is the most interesting and powerful tool of investigation especially when the officers have the proper knowledge of extracting it. Apart from identifying the source of a sample, DNA evidence can also locate the presence of an unknown individual at a crime scene where the suspect may claim not to have been. Furthermore, DNA evidence can reverse a claim of self-defense by placing a weapon in the hands of the suspect (National Institute of Justice, 2012). This type of evidence is interesting because it serves a broad purpose. When used correctly, it has the ability to change a narrative from an alibi to that of consent.
DNA evidence can be retrieved from firearms and other weapons, fingerprints, and foot wear among other objects and materials (National Institute of Justice, 2012). Body fluids like blood, semen, sweat, and saliva present on samples can be tested for DNA to identify a suspect. Other biological evidences that can be tested for DNA include skin, hair, and hair. Items like baseball bats or related weapons can have a suspect’s sweat, blood, tissue, or skin traces on the handle. For hats, masks or bandana, officers can check inside the items for dandruff, hair, or sweat. DNA can be obtained from used condoms, used cigarette, eyeglasses, toothpick, dirty laundry, stamp or envelope, bottles, beddings, bullet, and facial tissue among other surfaces (National Institute of Justice, 2012). DNA evidence is compelling not only because of its expansive use but also because it can be traced on numerous surfaces. Interestingly, DNA evidence, specifically nuclear DNA from semen and blood stains, can be traced from objects more than 20 years old using the polymerase chain reaction (National Institute of Justice, 2012). Samples such as very old bones, teeth, and hair strands can be used for mitochondrial DNA analysis too.
Proper organization is essential in crime scene investigation. Good planning ensures maximum collection of the readily available information at the crime scene to determine factors like the magnitude of the problem or establish what exactly happened. Proper organization helps the officers to determine possible hazards at the scene, whether specialized medical services are required, the local resources available, the personnel to be informed, or the equipment required among other significant factors (UNODC, 2009). Planning helps to manage delays by ensuring that the crime scene is well protected before the experts arrive. Once officers arrive at the crime scene, their organization and coordination is essential to ensure professionalism. Officers will ensure that all processes comply with the legal and ethical laws. They will determine which individuals to enter the scene first and how the required actions will be performed (UNODC, 2009). During the course of the investigation, organized officers will easily adapt to any changes whenever new elements are recognized.
Another important factor is the availability of the crime scene equipments. Potential hazards like chemicals, biological materials like infected blood, and unsafe structure can arise. Once officers determine the nature of the scene, they can carry protective equipments like gloves and helmets. Appropriate packaging materials and warning labels can be used when collecting sensitive or dangerous samples. Cameras, notebooks, and tape measuresare essential in documentation of significant information. Other important tools include adhesive tape, cotton tips, or tweezers, and packaging materials like containers to store sharp objects, bags, or boxes. Also, powders and other chemicals are used to detect fingerprints or blood traces. Hand-held light sources and magnifiers can also be used to enhance the search process.
National Institute of Justice (NIJ). (2012). DNA evidence: Basics of identifying, gathering, and transporting. National Institute of Justice. Office of Justice Programs. Retrieved from https://nij.gov/topics/forensics/evidence/dna/basics/Pages/identifying-to-transporting.aspx.
UNODC. (2009). Crime scene and physical evidence awareness for non-forensic personnel. UNODC. Retrieved from https://www.unodc.org/documents/scientific/Crime_scene_awareness__Ebook.pdf