Introduction
Forensic evidence forms an integral component in the investigation and prosecution of homicide crimes. Without forensic evidence, it would be impossible to prosecute a good number of homicide crimes whose weak link to the crime in many cases is evasive without forensic tactics. The belief is that people are more deterred to commit crimes when they realize that there is a great possibility of being caught. Forensic evidence is therefore key in discouraging and consequently reducing homicide crimes. Although these crimes have been rising in our society, it is very possible that such cases would be much higher in the absence of forensic evidence. Moreover, for a society to exist in harmony, peoples rights need to be protected meaning that perpetrators of homicide crimes need to be punished. Forensic evidence has greatly helped in this endeavor. However, the challenge that presents itself is that forensic evidence is sometimes a complicated process that may even implicate the wrong person. There are a number of issues that may arise in the process of collection and presentation of forensic evidence in a court of law for prosecution. (Naik, 2006)
Main body
Forensic evidence can be defined as the information at a crime scene such as DNA, blood, body tissues among others found at a crime scene through the application of technology and scientific methods that can be presented as evidence in a court of law. This information could be used to trace the perpetrator of the crime, the manner of death, the cause of death, the time death occurred among other critical information that is required. This evidence can be broadly categorized into the following four groups: body fluid and tissue, impressions, tissues and trace evidence.
Body fluid and tissue is mainly considered as the most important and common forensic evidence. This is especially true following the discovery of DNA- a unique component found in all body cells that can be related to a specific individual. Each person has a unique DNA. Moreover, the collection and storage of DNA data bank by several governments in the world makes it easier to find suspects of homicide crimes. Body fluid may be in the form of saliva, blood, vaginal fluids, and semen among others. Since homicide involves murder and violence, blood is very commonly found at scenes of murder. This could be blood from the deceased, the perpetrator of the crime or could even be a combination of the two. Blood can provide a lot of important information. The most obvious is that it can provide DNA, which could link a suspect to the crime. Besides, it can provide information on the health of the victim at the time of death. (Saferstein, 2007)
The pattern of blood can provide information on the manner of killing and retrace events that occurred just before and during the murder. On the other hand, body fluids like semen and vaginal fluids can likewise be used to trace events before, during and even after murder. Normally, physical evidence like body fluids is related to other reports which could for example provide information on the movements of the deceased. While some of this evidence can be easily seen, most of it requires scientific tools like special cameras and other special tools to find. Body tissues like skin tissues are also found in great quantities at murder scenes. Their pattern and nature can provide information such as the manner of death apart from DNA. An important approach that is normally taken by crime scene investigators is to find areas where tissues are missing in the body of the victim. This can be caused by mutilation from a suspect, gunshots, being run over by a vehicle, bites among others. The investigator can then go ahead to find the missing tissue maybe from a car that had hit the victim using several leads with a possibility of linking a suspect to the crime. (Saferstein, 2007)
Another category of forensic evidence is impressions which could be in the form of fingerprints, foot prints and foot wear prints (from shoes), bite marks, tire marks, ligaments among others. The body impressions of the victim are important in retracing the movements of the victim before, during and after murder since they can be referenced with other similar impressions. Besides, they can also be used to identify the manner of killing for example they can tell whether the victim was bound, strangled among other similar information. On the other hand, body impressions left by the suspect may be used to trace the suspect apart from providing information that could provide critical leads like the shoes that were worn by the suspect or the car that was used to murder the victim among other critical information. Moreover, body impressions of people around the murder scene could be used to identify people for questioning or those that could act as witnesses in court. (Naik, 2006)
Weapons are an important source of evidence in homicide investigations. An important consideration that is always taken is to ensure the safety of the investigators or other people that may be involved in the handling of the weapons calling for special methods of storing the weapons. These may include explosives, knives, and firearms among others. Firearms are the major cause of homicides in the United States. Information that can be obtained at the crime scene from such murders includes the relative position of the suspect and the type or the specific gun that was used to commit the crime. Methods like collection of fingerprints, collection and observation of dislodged tissue patterns are employed. (Saferstein, 2007)
Another important form of evidence in homicide investigation is trace evidence. This includes physical evidence that is found in trace quantities which can link a suspect to a crime. This evidence could include fibers, hair or even evidence that may be in the form of smells which can be taken as notes by a crime scene investigator. This evidence could be crucial in finding a suspect. For example, a carpet fiber that has been found on a dumped body could match with a fiber on the carpet of as specific car linking the owner of the car with murder. Likewise hair fibers may be found on the body of the victim. This could even provide DNA information, which can be searched on the DNA database to find the suspect. (Saferstein, 2007)
Conclusion
When properly administered, forensic evidence remains the most important evidence that can be used to link a suspect to a homicide. Issues that may arise in forensic investigations include the preservation of victim bodies and the possible prosecution of innocent persons who may not be able to explain how their tissues or other forms of forensic evidence has for example been found on the body of the victim. There is therefore need to maintain ethical standards, tactics and professionalism in the application of this important evidence.
References
Naik, S. K. (2006). Obliquity vs. discontinuity of ligature mark in diagnosis of hanging: a comparative study. Anil Aggrawal’s Internet Journal of Forensic Medicine and Toxicology, 7(1). Web.
Saferstein, R. (2007). Criminalistics, An Introduction to Forensic Science (9th Ed.). Upper Saddle River, NJ: Pearson/Prentice Hall.