Principles of Evidence Collection and Preservation

Principles of Evidence Collection and Preservation

Locard’s Principle

As objects or people come in contact with another person or object, there is a possibility that an exchange of fluids and or materials may take place (Lynch & Duval, 2011).  The exchange of fluids and or materials may prove significant when investigating the circumstances surrounding a crime. Physical evidence is extremely vital to a case in which a crime has been committed. The presence or absence of fluids and or materials can corroborate or disprove recollection of events. Physical evidence as in DNA does not lie. When there is DNA proving that someone was at a crime scene, it is very difficult to disprove. Physical evidence is a vital tool used in most crime cases to prove a crime has been made. However, evidence is only as valuable as it is kept. The chain of custody must be maintained strict with a minimum amount of people involved.

Locard’s exchange principle was developed by Dr. Edmond Locard. He speculated that every time there is contact with another person, object or thing, there are exchanges of physical materials taking place. Dr. Locard was widely known to the forensic field. He was born in 1877 in France. In 1902, he obtained a PhD in medicine. He then worked as an assistant to a forensic pathologist and years later he began his first step by pursuing his career. He created a crime laboratory in France in 1910 and wrote many books. He learned a lot about forensics through his partner, the father of medicine (Moore, 2016).

No matter where a perpetrator goes or what they do, when they come into contact with things, that criminal will leave an immense amount of evidence. The evidence can include but not limited to DNA, fingerprints, footprints, hair, skin cells, blood, bodily fluids, pieces of clothing, even tiny microscopic pieces, fibers and so much more. At the same time, they will always take away with them a piece of the scene. It is seldom that a crime takes place and a criminal leave no evidence behind (Moore, 2016). Traces of physical materials, such as trace evidence may be so miniscule that it may need a microscope and that is ok, there is no such thing as physical evidence too small and it may definitely tell a story. Physical evidence speaks as humans cannot, it does not lie and it is hardly ever wrong. The only time that physical evidence can be diminished is upon collection and preservation. The goal of the crime scene investigator is to recognize, document and collect evidence from the crime scene and anyone or anything that may have come in contact with the crime scene. Maintaining the chain of custody is of utmost importance thereafter.

Locard’s principle involve three major elements, victim, suspect and the scene of the crime. It is a web of who did what and what evidence was left behind.

Basic Steps in Evidence Collection

Evidence collection begins by approaching the scene carefully. The crime scene investigator must turn on the power of observation, everything that is smelled, seen or heard is potential evidence (Genge, 2012). There is a mental picture going on and digital still photography is often the first reaction for a CSI. The CSI may ask, does anything look out of place, or freshly disturbed? What odors may be noticeable and any unusual sounds if it is an outdoor, wooded crime scene? Security and protection of the scene follows and hopefully the first responders have not disrupted the potential physical evidence. All possible entries to a crime scene should be manned and blocked of anyone non-essential to that scene. Initiating preliminary survey follows as the CSI studies the scene. A walk around the scene, interior and exterior of the structure as needed and this includes open windows, damaged doors, ladders, etc. The CSI will first establish point of entry and other relevant information. During all of this time, the CSI should be recording everything and observing sensory. Evaluating physical evidence when possible is the very nature of what appears to be obvious and should trigger the thought processes of the CSI.

Chain of Custody

There are many ways evidence may be collected. The main importance with evidence collection is maintaining its integrity at all times. The most important aspect of forensic nursing is evidence collection and the need to maintain its integrity. For example, in a sexual assault allegation, the evidence collection and maintaining its integrity is crucially important to assure the perpetrator is punished extensively (Hammer, Moynihan & Pagliaro, 2006). Collection is the first step in evidence collection and labeling and packaging must be done systematically and extremely carefully as to not contaminate the evidence needed for a conviction. In forensic nursing, the chain of custody begins when a nurse locates and establishes that a potential item is a piece of evidence (Hammer, Moynihan & Pagliaro, 20016). The documentation process is vital as well in the collection of evidence. The documentation should be accurate and precise. Many items are needed, such as the date, time, location and proximity of the crime scene area.

Nurses and Familiarity with Evidence Collection

     The forensic nurse plays a vital role in evidence collection in numerous types of criminal investigations. The nature of forensic work indicates that those investigations will concern criminal acts of violence perpetrated upon victims (Hammer, Moynihan & Pagliaro, 2016). A forensic nurse is called upon to administer competent and caring health care and collect and preserve evidence of the crime in a manner that is scientifically and legally sound. The processing of crime scenes and the collection of forensic evidence in examinations performed on patients often are important in the process of solving and proving a crime. Unless all of the evidence in a crime is collected in a timely manner and preserved properly, the case may not be proven in a court of law, regardless of the act and regardless of the impact it may have had upon the criminal.

Forensic Knowledge Between Physicians and Nurses

  Forensic nurse examiners are fully qualified nurses and they are trained to gather forensic evidence in sexual assault cases. When victims are treated by forensic nurses it results in better outcomes than treatment by a physician. More rape kits collected by forensic nurses were admissible in a court of law than those collected by physicians (Moore, 2016). Forensic nurses are less expensive than medical doctors and many times the forensic nurses have more education and experience in forensics and evidence collection than physicians. There does not appear to be any benefit in terms of prosecution and conviction by substituting physicians with forensic nurses. However, the victims seem to be more comfortable and apt to speak with nurse examiners than a physician. Patients who suffer violent crimes such as rape and or sexual assault are likely to seek medical care in an emergency department. They may not always disclose the cause of their injuries leading to the impairment of evidence.

References

• Genge, N.E. (2012). The forensics casebook: the science of crime scene investigation. New York, NY. Ballantine Books.
• Hammer, R.M., Moynihan, B. & Pagliaro, E.M. (2006). Forensic nursing: a handbook for practice. Sudbury, MA. Jones and Bartlett Publishers.
• Lynch, V. A. & Duval, J. B. (2011). Forensic nursing science (2nd ed.). St. Louis, MO: Elsevier Mosby.
• Moore, P. (2016). The forensics handbook: the secrets of crime scene investigation. New York, NY. Barnes and Noble Books.