Scientific Method Applied to Forensic Science Paper

The Role of Forensic Science in Crime Scene Investigation
The scientific method begins with the identification of a problem. Questions are asked, data is collected, a hypothesis is formed and then tested. The scientific method is essentially no different from the kind of investigative work that investigators of a crime scene do on a daily basis. They a faced with a problem: a crime has occurred. The questions they must ask are: what happened, why, when, who was involved, where did it occur, and how did it happen? They collect data and using forensic science to analyze the data, they come up with a narrative that answers those questions (Shaler, 2011). Lab work helps to verify the story by providing more evidence that can give more details. This paper will show how the scientific method is applied to forensic science.
The forensic scientific method consists of five steps:
1. Acquisition of primary witness and other anamnestic evidence
2. Anticipation of future questions
3. Acquisition of physical evidence
4. Comparison of consistency of alleged events (hypothesis) with physical findings, obtaining additional data as needed
5. Assessment only to a reasonable degree of scientific certainty, recognizing the limitations of science (Young, 2020).
Forensic science is used to facilitate crime scene investigation. That is why the acquisition of primary witnesses as well as anamnestic evidence is important at the outset. Eye witness testimony provides the investigator with a sense of what happened based on what people saw. Anamnestic evidence gives an indication what people can recall about a situation.
In the scientific method, the first step is to observe and describe a situation. This allows the scientific researcher to understand what he is facing and what the environment contains. He lists everything he knows about the phenomenon so that he can look at all the facts and variables of a phenomenon and use this information to develop a thesis about what is going on. The same approach is taken with forensic science. The forensic scientist works closely with the crime scene investigator to ensure that the scientific analysis of data collected at the scene will inform the development of the investigator’s hypothesis.
The first step in forensic science is to observe and describe the scene. To analyze evidence, one must provide context. For example, the collection of fly larvae from the scene of a crime does not tell one much, but if it is collected from a corpse that was found floating in a shallow pool of water in the woods, it may say a great deal—such as how long the corpse had been there (based on growth of the larvae) and other insects at the scene could help to provide more clues as to the time of death. This description of the scene will be useful as the crime scene investigator collects eye witness testimony. For instance, in a murder scene, the crime scene investigator will interview eye witnesses and the forensic scientist will collect evidence from the scene of the crime. Together they will work to make sure nothing is left unexamined.
When arriving at the scene of the crime, the scene is first sectioned off so that there is one way in and one way out. This ensures that no one gets in to disturb the scene before it can be fully documented (Gaensslen & Larsen, 2019). The crime scene should be approached cautiously and the perimeter should be walked so that any evidence at the perimeter is also noted and collected. Sometimes evidence outside the crime scene can be found in this manner. This is consistent with the first step of the scientific method, which is to observe the situation closely.
The second step in the forensic science method is to anticipate what questions might be asked. So at the scene of the crime, the investigator must be able to guess what important questions will need to be answered and what evidence he should seek based on those questions. For instance, at the murder scene, the questions may include: What time did the murder occur? What was the murder instrument? Were there any drugs involved? Is there any evidence of a fight? Is the blood at the scene of the crime that of the victim or might it also be from the perpetrator? These questions and others like them will be used to guide the exploration and collection of the evidence.
Indeed, the second step leads directly to the third step, which is the collection of physical evidence. The investigator will collect samples of hair, blood, fibers, glass, soil, etc., so as to have an idea of what belongs organically to the scene and what was introduced externally by an intruder. This can give a sense of what to look for in terms of developing a picture of the suspect—perhaps by suggesting what he was wearing, where he had been walking, what type of hair he has, and so on. The collection of physical evidence follows fast upon the anticipation of the questions that are asked in the second step of the process.
The physical findings are then compared with the hypothesis put forward by the investigator in the fourth step to see if the evidence is consistent with the narrative that the investigator puts together. It also indicates whether more evidence is required. For example, the investigator may hypothesize that the murder suspect was there to rob the house and killed the home owner with a blunt object taken from the mantle when he was surprised by the home owner. There was a conflict and as struggle and the home owner was killed. This would be the hypothesis and the evidence obtained at the scene should support that story. There should be signs of a struggle, evidence of an illegal entry, signs of a burglary, and use of a murder weapon. If the evidence does not support the hypothesis, either a new narrative will be needed or more evidence must be obtained.
The final step is to assess to a reasonable degree of certainty the evidence and to be honest about its limitations. For instance, there is a common assumption that DNA testing is foolproof but the reality is quite the opposite. DNA evidence is helpful in ruling out certain groups of people—but it is not 100% foolproof in terms of being able to identify a suspect. The same goes with finger print identification. Mistakes have been made in the past wherein an innocent person is apprehended and charged with a crime because his finger prints were found at the scene or because someone with similar finger prints had been there. The tools of the forensic scientist are there to assist in the investigation but they are not the end-all-be-all of crime scene investigation. It is important to understand that.
Even in the scientific method, it is generally understood that the findings after an hypothesis is tested are not always going to tell the whole story. There may be other variables that were not considered that are having an impact on a phenomenon. There may be other areas of study need to be explored more before a complete or fuller understanding of the situation can be obtained. The limitations of forensic science are similar. The science is only going to tell as much as what one is able to see from the evidence collected. It is like having a narrow window into what happened. A fuller picture has to be developed by implementing traditional police work, interviewing witnesses, developing a profile of the suspect, and so on.
In the scientific method the hypothesis will predict the existence of other phenomena or predict the results of new observations. These tests of predictions must be verified by independent experimenters, who follow up on the work that others have done and reproduce the trial to make sure it was conducted correctly. In forensic science, lab work has to be verified and the chain of custody of evidence has to be carefully safeguarded—otherwise the defense will claim that the evidence has been corrupted and it will not be admissible in the court of law.
In conclusion, the scientific method guides the forensic science practice in crime scene investigation. It allows those investigating a crime to approach it systematically, by approaching it in the same manner that a scientist would a phenomenon or problem in the field that he wants to solve. First, he has to approach it, describe what he sees, walk the perimeter so to speak, and identify the clues that he sees. He has to anticipate the questions that need to be answered, obtain evidence from eyewitnesses and physical evidence from the scene of the crime, test the evidence to see whether it aligns with the hypothesis developed by the investigator, and recognize the limitations of the lab work in forensic science. These steps, if followed, will help the investigator to put together a fuller picture of what happened.
References
Gaensslen, R. E., & Larsen, K. (2019). Introductory forensic science (2nd ed.). Retrieved from http://content.ashford.edu/
Shaler, R. C. (2011). Crime scene forensics: A scientific method approach. Taylor & Francis.
Young, T. (2020). Forensic Science and the Scientific Method. Retrieved from http://www.heartlandforensic.com/writing/forensic-science-and-the-scientific-method#table3