In present day we know the Locard’s Exchange Principle. Which was developed by Edmund Locard a French scientist who believed any interaction between humans will leave some type of trace (Saferstein ,2011). Regardless of the scenario, when people interact every individual will carry something away from one another. Some of these transfers may need special tools in order to be retrieved seeing as some transfers may be invisible (Ramsland, 2012). Since Locard’s Exchange Principle is seen to be the foundation of forensic science, it is easy to see how important it is while looking for evidence at a scene of a crime. Small fragments of fiber, hair clothing or maybe even glass can be found at any crime scene which in turn could have been transferred to the assailant. That being said, it could help with the identification of an offender.
Trace Evidence Unit
Seeing how essential and influential trace evidence is, the collection of it to find criminals is important and highly needed. Trace evidence is examined through multiple tools which are used to locate and compare the sample’s physical and chemical properties (Saferstein, 2011). However, trace evidence is still overlooked due to DNA and fingerprinting. Trace evidence can give us vital details such as hair, paint, fibers, glass and even some chemicals. These reasons alone make it essential to create a trace evidence unit. In creating this specialized unit, trace evidence can be looked into more and thus provide more information that could be determining factors in cases. This proposal will discuss the functions of this unit, the importance of the forensic examinations and the specifics on how this unit will benefit police and investigators in solving crimes.
To reiterate, everyone meets other people and in such trace samples of one another are passed unwillingly and unknowingly. In turn, investigators are taught to search for the most insignificant piece of evidence within a crime scene (Spitz, Clark, Fisher, & Spitz, 2006). Traces are very difficult to locate because of this search patterns are conducted to avoid a duplication or overlapping of efforts. In doing so, this helps to minimize the processing of the crime scene. When conducting searches, investigators look on the victim or suspects clothing, the location in which the crime was committed and even a past location where the suspect was prior to the incident (Houck, 2003).
Once trace evidence is located the way in which it was collected is crucial regardless if the sample is small or looks insignificant. The care in which samples are collected can minimize the risk of mishandling evidence and minimize the transfer of evidence once the assigned investigator arrives on scene (Deedrick, 2000). A technique that should be conducted by investigators handling evidence is to, prioritize each piece of evidence by the relative value it presents to the criminal investigation (Saferstein, 2011). Identifying the culprit to a crime can be accomplished with proper search and trace evidence collection.
In a specific instance, the FBI truly understood the need for a specialized trace evidence unit. It was 1996, when 16-year-old Sofia Silva was abducted from her home in Spotsylvania, Va. (ABC NEWS, Accessed 2018). Her body as well as Kati and Kristin Lisk appeared lifeless with limited clues on how or who committed this crime. No witnesses and hardly any evidence left on the bodies except for a few tiny fibers and a couple of strands of hair (ABC NEWS, Accessed 2018).
Lead investigator Deedrick had everyone searching for a pink bathmat and also for anything that had blue fiber material. He believed all of the murders were connected but had very limited means in determining if that was the case. Fast forward to 2002 in which a 15-year-old was abducted in daylight via gunpoint in Colombia, S.C. The kidnapper, forced her to climb into a container in the back of the car (ABC NEWS, Accessed 2018). Luckily for her while her captor slept she was able to escape and lead police back to the individuals home.
The captor was identified as 38 year-old Richard Marc Evonitz. He ultimately fled the scene and committed suicide. Investigators were still left with the question of is this the serial killer we have been looking for all this time. Deedrick, searched the man’s apartment for any clues that could link the perpetrator to the other crimes. In searching his home, investigators were able to find he once lived in Sposylvania, where the first murders were committed. He dusted fingerprints inside of the truck finally, he was able to locate four fingerprints after finding those prints and some small fibers around the dwelling Deedrick raced back to the forensic lab with over 600 pieces of evidence (ABC NEWS, Accessed 2018).
Deedrick noted some forensic matches the pink bathmat that was searched for over five years was found and also some furry handcuffs that had blue fibers. These two pieces of evidence combined with the trace evidence found in previous murders linked this man to all of them (ABC NEWS, Accessed 2018). If this investigator had not focused on these two what seemed insignificant pieces, the families of these victims may have never been giving closure for the deaths of their children.
When we look at most crime labs, some have a type of trace evidence unit. These examiners have various backgrounds due to the varying forms of trace evidence that can be found at crimes scenes. Thus, varying forms of certification will be required. Saferstein (2011) explains on what the American Board of Criminalists provide on their General Knowledge exam. In order to be a certified trace examiner, one must pass the general knowledge exam and in order to be certified in a specialty such as fibers, glass or another discipline a specialty exam must be taken.
The Scientific Working Group for Material Analysis has a set quality standard that provides guidelines to labs and ensures good practices are conducted from all analysts in any region (Houck, 2003). The local police station in which this unit is attached to must also ensure their own rules and regulations to ensure quality work is being conducted. An accreditation from The American Society of Crime Laboratory Accreditation board and ANSI-ASQ National Accreditation Board should also be pursued to have regulated quality control. As mentioned previously, having good evidence collection techniques and procedures will help to ensure the possibility of capturing an assailant.
Trace evidence is seen as hair, fiber, glass and paint all of which are beneficial tools that can assist investigators in locating or identifying criminals. In developing a specialized unit whose sole focus is the collection and further developing of these samples is key. This unit will give back time to investigators who can focus their efforts on interviewing and possibly finding another avenue in solving a crime. Therefore, having this unit embedded into a crime lab is imperative and not a lucrative idea. Regardless of situation, everyone comes in contact and leaves something of themselves behind. This field is known to pay attention to the details and this is a detail that needs further digging. What may seem unimportant, can ultimately be the last step an investigator needs to be able to call a case closed.
- ABC NEWS. (Accessed 2018, March). Retrieved from http://abcnews.go.com/GMA/story?id=125152
- Deedrick, D. W. (2000). Hairs, fibers, crime, and evidence. Forensic Science Communications, 2(3).
- Houck, M. M. (2003). Trace evidence analysis: More cases in forensic microscopy and mute witnesses. Academic Press.
- Ramsland, K. (2012). Locard’s vision: 100 years of crime labs. Forensic Examiner, 21(2), 60.
- Saferstein, R. (2011). Criminalistics: An introduction to forensic science, 10th Edition. Retrieved from https://bookshelf.vitalsource.com/#/books/9781269456616/
- Spitz, D.J., Clark, R., Fisher, R.S., & Spitz, W.U. (2006). Spitz and Fisher’s medicolegal investigation of death: Guidelines for the application of pathology to crime investigation (4th ed.). Springfield, IL: Charles C. Thomas.