Preserving Biological Evidence

Physical evidence left behind at a crime scene plays a crucial role in reconstructing the events that took place involving the crime. Bloodstain pattern analysis (BPA) is a discipline which utilizes the sciences of biology, physics, and mathematics. Bloodstain interpretation may be accomplished by direct scene evaluation and/or careful study of scene photographs in conjunction with detailed examination of clothing, weapons, and other objects regarded as physical evidence. The location, spreading, and appearance of bloodstains and spatters can be useful for interpreting and reconstructing the events that produced the bleeding. An investigator or bloodstain pattern analyst can decipher from individual bloodstains the direction and angle

It’s important that all evidence is identified so that forensic scientist can examine it and take

Forensic evidence has been shown to be reliable due to many factors of evidence such as DNA, blood, fingerprints, etc.; however, many cases have shown that

While entering the crime scene, the first responding officer should look out for any evidence which is present on the ground. There have some cases in which the first responding officer stepped on the evidence such as blood or

Thoroughly document scenes and gather potential evidences (physical, specimens, documents, photographs, statements etc) to send to crime lab

Hair and blood are two of the most common pieces of evidences found at the

After the crime is first reported, the law enforcement officers must open an investigation. Within the investigation, witnesses must be interviewed separately by police, along with the victims, and suspects. Crime scene technicians should also be contacted to collect any type of evidence from DNA, fingerprints, and blood samples. After possible incriminating evidence is collected, it must be sent back to the lab for testing.

Hair is very useful evidence in helping to determine things in a crime. Hair starts growing out of your pores, starting with the hair follicle and is composed of three principle parts. The three parts are the cuticle, the cortex and the medulla. If examined closely, hair strands can play a major part in solving a crime/case. Although hair is class evidence, individual characteristics can narrow down the evidence to a single source.

Forensic DNA Phenotyping is a new and emerging field of forensic science. As it is so new, there is very little in terms of literature on this field, very little testing done on this type of identification, and few cases that have used DNA Phenotyping to assist in the investigation. The first documented case of DNA Phenotyping being used is in the early 2000s, so it has had under 20 years of research and experimentation with it. There are many weaknesses to the version of DNA Phenotyping that is available for use so far, but once there is more research done on it, and more experimentation with this new science, DNA Phenotyping could easily be a major tool to investigators around the world.

As such it incorporates a vast array of disciplines, such as biology and physics and further applies this knowledge to the realm of forensic science (Bevel, & Gardner, 2008). BPA can be directly accomplished through the analysis of physical evidence at the crime scene in conjunction with photography, and/or through the thorough examination of other classes of physical evidence, such as weaponry and clothing (James, Kish, & Sutton, 2005). The analysis of bloodstain patterns provide the investigators of an incident with an extensive assortment of information relative to reconstructing the crime scene (Karger, 2008). Information provided can extend from the positioning of the victim during the bloodshed, the movements of the perpetrator, the mechanisms to which produced the bloodstains, and so forth (James, Kish, & Sutton, 2005). Therefore, the application of BPA assists the investigator in answering what events had occurred and in what sequential manner, where the events occurred and where people were situated, and what did not occur (James, Kish, & Sutton,

Generally, many types of forensic evidence are often considered scientific evidence, like DNA matching, fingerprint identification, and hair/fibre evidence. The methods used to develop these types of evidence are generally beyond the scope of knowledge that judges and juries possess and are therefore normally introduced as scientific evidence. In general, a scientific theory must have established itself in the scientific community and become generally accepted as the truth before it will be asserted as evidence at trial. For example, because it has been around for so long and because it has proven to be reliable, evidence regarding fingerprint matching is generally admissible as forensic evidence in trial. In addition, things like radar and laser speed guns are generally accepted as being a valid method to tell the speed of a car at a given time and can be admitted as evidence. There will often be new types of scientific evidence that parties will attempt to submit at trial - science that may not have a solid foundation within the scientific

After doing their job in he crime scene, the evidence they took will be taken to the forensic scientist. Crime scene investigators will look at the photographs and connect their theories based on the crime that occurred. The forensic scientists will also examine the victim’s clothes, while the medical examiner will analyze the victim’s body for more clues and evidence that they may find and they will all be doing this in the crime lab. The things they may find could be hair, fiber, semen, blood, another person’s DNA, bruises and many more. After the forensic scientists

The book gives a general overview of the field of forensic science. The sections of the book include “The Scene of the Crime; Working the Scene--The Evidence; Working the Scene of the Body Human;

Criminologists, usually Forensic scientists, collect DNA sources of semen, saliva, hair follicle, body cells, skin, and blood. They must always wear gloves, mask, and use disposable instruments. This help prevents the DNA being contaminated, to where it would not be useable. The collected samples must be bagged and label in envelopes but not plastic bags! Plastic Bags retain moisture that will damage DNA, another reason why DNA must be protected and label is that direst sunlight and weather condition may damage DNA.

Recent advancements in DNA technology have improved law enforcement’s ability to use DNA to solve old cases. Original forensic applications of DNA analysis were developed using a technology called restriction fragment length polymorphism (RFLP). Although very old cases (more than 10 years) may not have had RFLP analysis done, this kind of DNA testing may have been attempted on more recent unsolved cases. However, because RFLP analysis required a relatively large quantity of DNA, testing may not have been successful. Similarly, biological evidence deemed insufficient in size for testing may not have been previously submitted for testing. Also, if a biological sample was degraded by environmental factors such as dirt or mold, RFLP analysis may have been unsuccessful at yielding a result (Turman).