Investigation Procedures of Evidence Gathering and Chain of Custody

Type of forensic evidence

Biological evidence

Blood

In forensic investigation, blood is used to examine the physical evidence. The discipline of examining blood is known as bloodstain pattern analysis and the process involves analysis of the bloodstains and the activities which led to the bloodshed. The role of bloodstain pattern analysis (BPA) is to help understand violent crimes through tests and experiments (Augenstein, 2017). Analysts  in this process produces accuracy and quality information by employing two procedures namely; pattern analysis’-a process which aids  in investigating the sequence of action, position of the victim, type of weapon and  other related  things which could have contributed to the bloodshed. The second process is reconstruction and it involves the process of evaluating event series during occurrence of crime and aftermath (Augenstein, 2017).

 

 

Investigation process

 

  In biological evidence, bloodstain pattern analysis requires adequate proficiency, formal instruction and experience in order to produce reliable results. Other point is that the group of disciplines aids in crime investigation and investigators gains a wealth of information.

Forensic pathologists play a fundamental role in examining DNA individualization in autopsy examination (Edwards, Body & Ferner, 2012). Bloodstain pattern analysis is done through various methods such as scene evaluation, examining scene photographs, clothing and more. In DNA, analysts gains valuable information from bloodstain pattern and he or she is able to understand the timeline of events and to judge whether bloodstains are associated with crime. Bloodstain pattern analysis acts as a valuable tool in investigating crimes and through analysis, analysts are able to use contextual information and reach the conclusion. In biological evidence, bloodstain patterns are categorized into dropping bloodstain patterns and the evidence taken in this category is based on liquid blood which is taken from physical and biochemical properties’. The blood drops from the liquid blood has a high viscosity (Edwards, Body & Ferner, 2012). Second is impacted bloodstain and this is blood which comes from both internal and external force. Third is blood dripping and this produces bloodstain pattern during bloodshed. Reconstruction is done with bloodstain patterns and documentation techniques are used. Techniques such as photography are valued as a basic process which involves scales which provides documentation dimensions. Sketching is also a technique used in placing bloodstain pattern in scale for reconstruction purposes (Edwards, Body & Ferner, 2012).

 

 

 

Before the investigation process, the crime scene is protected in order to do the investigation thoroughly. Several photographs are taken at the crime location for further investigation. Before investigation, investigators are advised not to touch anything, they are supposed to use different angles in taking photographs and team members should join hands to do a thorough search (Porter, 2011). Bloodstain pattern analysts may use a rough sketch which will aid during the process of investigation. Investigators carry the process of collecting, documenting and storing the blood evidence and bloodstain analyst examines the events and produces facts based on the crime. The analyst observes the bloodstain and pattern in order to draw conclusion. In gathering evidence, the analyst examines the bloodstains pattern in terms of grouping and arrangement in order to understand the static consequences (Porter, 2011). To examine the evidence, the analyst conducts an effective search by gathering evidence from the whole scene in order to gain deep truth. In examining the bloodstain, the analyst gains information such as the  objects used in shedding blood, the droplets, the position of  suspect, victims, the nature of objects and force. Using the bloodstain pattern, the analyst is able to produce a generalized reproduction (Porter, 2011).

 

  Crime scene reconstruction

 

            The physical evidence gathered by investigators together with laboratory examination is analyzed. Analysts play a significant role in carrying out scientific scene analysis, analysis of the scene pattern, laboratory examination and systematic study in the formulation of theories.   Reconstruction is important in producing the actual course and making observation through physical evidences and employing logical approaches (Parmar, 2015).With respect to the forensic science, reconstruction is done by applying scientific principles and logical methodologies. Investigative information is required as well as logical and considerable experience. In investigating physical evidence, there must be basic principles such as the theory of transfer. Other important point to note is that bloodstain pattern reconstruction is reinforced by law enforcement and it is done to understand the physical nature and investigation facts. Reconstruction is done aftermath and its purpose is to analyze the actions which led to the bloodshed (Parmar, 2015). The bloodstain patterns produces effective results by offering answers based on ‘what’. Recognition is a procedure used in analyzing the potential evidence. During the investigation process, a lot of information is collected and analysts eliminate the information which has no evidential value. The analysts preserve and document the evidence. Laboratory analysis is also used to examine the substances and is compared with other known materials to come up with individualized evidence (Parmar, 2015). Before reconstruction, recognition is a key element. In the identification process, biological evidence is compared with other evidence such as morphological properties, chemical properties and others. In this process, a logical process is needed in individualizing a person.

 

Evidence from blood pattern is derived from teamwork concept.  In general, forensic science is related with criminal justice system and research and development is made by law enforcement agencies. The methodologies used are aligned with validation of techniques, documentation and codes of practice. Dissemination is also considered as it is the key element in producing clear and appropriate explanation to the judges (Aleksander, 2012). In forensics science, effective communication is required for the purpose of eliminating obstacles and enhance environment for opportunities and requirement. In order to understand how blood provides evidence, it is important to remember that blood has complex mixtures such as cells and other inorganic substances. Plasma is a fluid found in the blood and it contains cells and platelets. The blood cells contain antigens which produces the blood type. In the discipline of forensic science, blood is used to derive the evidence (Aleksander, 2012). In investigating the crime, investigators analyze both dried and wet bloodstain in the crime scene. Wet blood is valued more than dried blood since it produces reliable tests. In addition, wet blood is in liquid from and so little storage is required compared with dried blood.  Dried bloodstain can also be used and should be collected using cotton-tipped swab (Aleksander, 2012). It also has benefits since it does not interact with bloodstain. In the investigation process, Locard exchange principle is used to help the investigators understand that there is exchange of blood. Thus, it is advisable to carry out medical examination and collect physical evidence from the victims. In the investigation process, the collected blood is stored and preserved with EDTA preservatives for the purpose of conducting DNA test or other analysis. It is also advisable to collect blood from different parts of the body such as heart especially when investigating dead bodies. The collected blood should put stored in an airtight container (Aleksander, 2012). In the crime scene, investigators identifies bloodstain and they use precautions when collecting preserving. The collected blood is put in vacutainer to preserve the blood. The blood is transported to the laboratory where various chemical tests are done.

 

Last, the research has shown that in investigating and solving crimes, various techniques such as fingerprinting are used. However, there are other effective technological techniques which help law enforcement understand the suspect.  DNA test is used as an investigative tool and this methodology is highly variable (Van der Gronde et al, 2014). Forensic scientist gains reliable information and are able to clearly identify individual at the crime scene. In crime investigation, forensic science is applicable in observing, identifying, offering description, conducting experiential investigation and offering theoretical explanation. Among many evidences, DNA evidence has aided the criminal justice system in identifying suspect and arresting them. DNA profiling is used as an essential tool in detection and crime prevention.  In forensic field, biomedical research provides genetic techniques in investigating the crime. The criminal justice system and law enforcements use the DNA databases in investigating and solving crimes. The forensic analysis is done to collect and analyze the evidence (Van der Gronde et al, 2014). Law enforcement use DNA to analyse wrongful conviction, for identification purposes and gathering information through testing materials found at the crime scene. Generally, biosocial criminology has gained momentum in investigating crimes and arresting offenders.

 

 

 

 

 

 

 

 

 

Reference

 

Augenstein, S. (2017). Is Forensic Science Tipping the Scales of Justice?. Laboratory

Equipment, 53(8), 8-11.

 

Aleksander, A. (2012). Forensic expertise and judicial practice: evidence or proof?. Journal Of

Evaluation In Clinical Practice, 18(6), 1147-1150. doi:10.1111/jep.12007

 

Edwards, I. R., Body, D., & Ferner, R. (2012). Toxicological evidence in forensic

pharmacology. International Journal Of Risk & Safety In Medicine, 24(1), 13-21.

 

Porter, G. (2011). A new theoretical framework regarding the application and reliability of

photographic evidence. International Journal Of Evidence & Proof, 15(1), 26-61.

doi:10.1350/ijep.2011.15.1.367

 

Van der Gronde, T., Kempes, M., van El, C., Rinne, T., & Pieters, T. (2014). Neurobiological

Correlates in Forensic Assessment: A Systematic Review. Plos ONE, 9(10), 1-15.

doi:10.1371/journal.pone.0110672

 

Parmar, P. (2015). Reconstruction of crime - A review. International Archives Of Integrated

Medicine, 2(10), 49-53.