Forensic Science and its 9 Governing Principles via The Legal Conundrum

The word ‘forensic’ is derived from the Latin word ‘forensis’ that relates to a discussion or examination performed in public. Forensic science is the application of science and the scientific method to matters of law and resolution of legal conflicts. It is a multi-disciplinary subject which draws upon physics, chemistry, biology, computer science and other scientific principles and methods and is concerned with the recognition, identification, individualisation, and evaluation of physical evidence.

As society moves towards more scientific response to solving crime, significant advances have been made in the fields of serology, fingerprint and footprint analysis, handwriting analysis, ballistics and toxicology among others. Forensic scientists study and interpret the different types of evidence found at a crime scene. They employ techniques and tools for recovery and collection of crime scene evidence, so as to ensure that criminal evidence is recovered and retained without being contaminated and altered, packed and sent in a scientific and safe manner to the laboratory where the latest techniques are deployed and applied to extract prosecutable evidence that will link the evidence to the scene of crime and finally to the criminal so that he or she may be successfully prosecuted. Forensic scientists not only analyse and interpret evidence but also provide expert witness testimony in the Courts.

Forensic science has developed its own laws and principles. They guide the disciplines and methodologies of science in analysing the evidence impacting the proceedings in the Court of law. The following laws and principles are essential in crime scene investigation to link a suspect to the victim and the crime scene.

1. Locard’s Exchange Principle

Edmund Locard (1877-1966)
Edmund Locard (1877-1966)

Edmund Locard (1877-1966), a French scientist postulated the exchange principle in 1928 which asserts that every contact leaves a trace.

According to Locard, when a person or his instruments comes into contact with another person or object, a cross transfer of materials occur. They leave trace, and likewise pick up traces from the same contact. Such transfer or exchange may be large or small, visible or invisible, readily detectable or difficult to detect. It is the responsibility of the Investigating Officers to search, identify and collect such evidences.

Thus, a mutual exchange of traces takes place between the criminal, the victim and the objects involved in the crime. Every criminal can be linked to a crime by dust particles carried from the crime scene. For instance, in a case involving counterfeit coins, Locard asked the police to bring the three suspect’s clothing to his lab. After examination he recovered small metallic particles from the cloth material which made up the composition of the coins. Confronted with this evidence, the suspects were arrested and soon confessed to the crime.

2. Principle of Evidence Recovery

The principle of evidence recovery provides that no harm should be done to the evidence. Nothing should be added, lost, damaged or obliterated in the recovery process.

Careful attention should be taken to avoid contamination. Great care should be taken when there is a risk of losing or damaging evidence. Exhibit items need to be safely and securely packaged and transported to the laboratory.

3. Law of Individuality

Paul L. Kirk (1902-1970)
Paul L. Kirk (1902-1970)

Law of individuality is attributed to Paul L. Kirk (1902-1970) and provides that two objects may be indistinguishable; however no two objects are identical.

Individuality implies that every entity, whether person or object, can only be identical to itself and so is unique. It expresses that all articles or objects, man-made or natural, possess an individual character which under no circumstances is duplicated. Everything involved in a crime has an individuality which when established connects the crime to the criminal. The reasons for this could be either minor flaw present in the raw material, or imperfect stamping or variation in configuration of the crystals or substitution of some quantity of extraneous matter.

4. Law of Progressive Change

Law of progressive change provides that everything changes with the passage of time.

Change is inevitable. Different types of objects may take different time spans. Sample degrade with time, bodies decompose, firearm barrel loosen, tire tracks fade, metal objects rust. The scene of occurrence undergoes rapid changes.

5. Principle of Comparison

Principle of comparison asserts that only the likes can be compared. It emphasises the need of providing like samples and specimen for comparisons with the questioned items. A questioned hair can only be compared to another hair sample, likewise with blood samples, bite marks, tire marks, tool marks, etc.

Two objects are said to match when there are no unexplained, forensically significant differences between them.

If a comparison is conducted as the final and ultimate test, the rule is if in doubt, exclude. Whereas, if the comparison is conducted as a screening prior to the other tests, the rule is if in doubt, include.

6. Principle of Analysis

The principle of analysis stresses on the need of correct sampling and correct packing for effective use by experts. The quality of any analysis is determined by the quality of the sample under analysis, the chain of custody, and the expertise of the individual who analyses it.

The analysis can be no better than the sample analysed. Improper sampling and contamination render the best analysis useless.

7. Principle of Presentation

The principle of presentation provides that the laboratory report should be readily understandable and impartial. It should neither be understated, not overstated.

Complete disclosure should be made of all facts, assumptions, data, conclusions and interpretations.

8. Law of Probability

The law of probability asserts that all identification, definite or indefinite, is made, consciously or unconsciously, on the basis of probability.

Probability determines the chances of occurrence of a particular event in a particular way.

9. Law of Circumstantial Facts

The law of circumstantial facts has its basis in ‘facts do not lie, men can and do’.

The oral testimony depends upon the power of observation, assimilation and reproduction of the witness. It may be disturbed by rationality, external influence, suggestions, descriptions and opinions of others. Whereas factual evidence is free from these infirmities.

Thus, evidences given by victims or eye witnesses may not always be accurate. Sometimes they may intentionally lie or make up facts, or exaggerate or make assumptions or give evidence while having to rely on their poor senses.  On the other hand, evidence which gives a factual account e.g. based on investigation and evidence has a higher chance of being accurate and is more reliable.

The word ‘forensic’ is derived from the Latin word ‘forensis’ that relates to a discussion or examination performed in public. Forensic science is the application of science and the scientific method to matters of law and resolution of legal conflicts. It is a multi-disciplinary subject which draws upon physics, chemistry, biology, computer science and other […]

Forensic Science and its Governing Principles and Laws — The Legal Conundrum

How to Catch a Liar via Brainwave Science

According to Brainwave Science an average person hears about 200 lies every day. It is no surprise as we learn how to lie in our early development stages and by the time we become adults, we get pro at lying! The only catch here is the question, ‘how to catch a liar?’

Technological advancements in different fields of crime scene investigation have drastically changed the landscape. Today, law enforcement can use technology to detect and solve criminal activity happening at the moment. The approach is more proactive than reactive. Forensic Science has completely changed the way crimes are investigated, prosecuted, and adjudicated.

Biometrics work very well to confirm the identity of the person. They are being utilized in ID cards, bank cards, phones, and other technological devices and come in various forms such as fingerprints, irises, voice patterns, and the spatial geometry of the faces, etc. Biometric systems must be able to accommodate changes to the biometric over time which may be caused by aging, illness, or injury.  Let us not forget though that external subject identification via its Automated Biometrics Identification System aims to ensure national security and public safety. It can only, however, identify the person’s identity externally, but not the mind and schemes of the person.

Brain Fingerprinting – This technique is quite ideal for discovering if a piece of information is collected in a person’s brain through EEG. It correctly measures the electric brainwaves science which helps us tap into the person’s familiarity with the crime scene. The major challenge in using this technique is the need for extensive training and the cumbersome nature of software and hardware application needs specialized neuroscientists to administer tests that may not be learned by investigators. It is more of a service-based model where the expert is needed to constantly conduct testing.

iCognative technology is the only available neuroscience-based forensic technology that is over 99.9% accurate, applicable in almost all investigations, is based on proven P300 science, has been used in over 100 real-life cases, and is virtually unbeatable. Today many countries and intelligence agencies in the world are already reaping the benefits afforded by it. To top it all it supports human rights and eliminates torture.

iCognative technology:

  • identifies criminals from innocents, detects presence or absence or information in the brain
  • specifically screens privileged information holders, specific training like IED/EOD bomb-making
  • helps apprehend terrorism and crime supporters and sympathizers
  • helps identify foot soldiers from kingpins in organized crimes
  • successfully detects intent to harm and cause violence

distinguishes between witness and perpetrator

DNA and Fingerprints are the first go-to methods for all investigations. They are accepted as a piece of evidence in the court of law. However, the issue with them is that the crime scene must remain uncorrupted and the collection of evidence must be done properly to eliminate cross-contamination. Preservation of these evidence is also a labor-intensive task that must be conducted by professionals who have been extensively trained in this field.

Lie Detector/Polygraphs are not accepted as evidence but are extensively used by law enforcement agencies to eliminate innocents from the suspects. The accuracy rates of Lie detectors or Polygraph has been hotly debated. People are able to beat them, and the interpretation of results is done subjectively by the examiner. Most psychologists agree that there is little evidence that polygraph tests can accurately detect lies – American psychological Association (APA)

 

Did you know that an average person hears about 200 lies every day? It is no surprise as we learn how to lie in our early development stages and by the time we become adults, we get pro at lying! The only catch here is the question, ‘how to catch a liar?’ Technol

Ethical Dilemmas in Forensics

Most forensic “scientists” have little understanding of scientific methodology, do not design or conduct research (and do not know how to), often have not read the serious scientific literature beginning to emerge in their fields. . . . Scientific findings relevant to a given forensic science often are ignored in the conduct of everyday casework.
via: Salem Press Encyclopedia of Science
Abstract:
Although witnesses in American courtrooms are called upon to tell the truth, the whole truth, and nothing but the truth, they may be enjoined from volunteering information. A witness’s individual sense of relevance must often bow to a court’s judgment. The legal system seeks truth, yet it sometimes defers to other values, such as fairness and confidentiality, and in general demands acceptance of formalized rules of procedure. In their capacity as experts, forensic scientists typically enjoy greater latitude than ordinary witnesses in expressing opinions and making judgments in the courtroom, but they too must operate within the often cumbersome and sometimes counterintuitive requirements of the “system” of “justice.”

Definition: Principles of conduct, moral duty, and obligation that guide individuals in their decisions and actions.

Significance: As scientists, forensic scientists have a professional obligation to seek and to speak the truth about matters within their purview. As participants in a forensic process, they are subject to additional, sometimes conflicting, duties. This tension generates many ethical dilemmas.

Although witnesses in American courtrooms are called upon to tell the truth, the whole truth, and nothing but the truth, they may be enjoined from volunteering information. A witness’s individual sense of relevance must often bow to a court’s judgment. The legal system seeks truth, yet it sometimes defers to other values, such as fairness and confidentiality, and in general demands acceptance of formalized rules of procedure. In their capacity as experts, forensic scientists typically enjoy greater latitude than ordinary witnesses in expressing opinions and making judgments in the courtroom, but they too must operate within the often cumbersome and sometimes counterintuitive requirements of the “system” of “justice.”

89312142-73888.jpg
Entrance sign at the Society of Forensic Toxicologists (SOFT) Meeting, July 5, 2012. By Monika M. Wahi (Own work) [CC-BY-SA-3.0 (http://creativecommons.org/licenses/by-sa/3.0)%5D, via Wikimedia Commons

Forensic scientists are measured against a standard of professional integrity, although the professionalization of the scientific study of crime is far from complete. Professions are substantially self-regulating, usually through agreed-upon standards and codes of ethics, and this creates the need for them to articulate appropriate expectations and the responsibility of members of professions both to act correctly themselves and to provide appropriate correction for their errant colleagues. A case in point is William Tobin’s campaign against the chemical analysis of bullet lead, also known as comparative bullet-lead analysis (CBLA).

Tobin’s Exposure of CBLA

CBLA is a technique that the Federal Bureau of Investigation (FBI) used for four decades—the investigation of the assassination of President John F. Kennedy in 1963 was an early use—to make cases against defendants when traditional firearms analysis (that is, examination of barrel rifling on bullets) was not possible. By measuring the proportions of seven trace elements (antimony, arsenic, bismuth, cadmium, copper, silver, and tin) found in the lead of a bullet in evidence, forensic scientists sought to establish the probability that the bullet came from the same provenance as a bullet in the suspect’s possession. The belief that the comparison of the chemical composition of bullets could connect two bullets rested on unexamined assumptions about the similarities and differences of the source lead from which the bullets were cast. FBI experts testified in thousands of cases that the facts ascertainable through CBLA established likely identity and therefore pointed toward the probable guilt of the accused. Sometimes, as in the case of Michael Behm, who was convicted of murder in 1997, CBLA provided essentially the only evidence of guilt.

In the 1990s, FBI metallurgist William Tobin began to question the validity of the technique. He felt strongly enough about the issue to research the matter, after his retirement in 1998, with Lawrence Livermore National Laboratory metallurgist Erik Randich. They analyzed data from two lead smelters in Alabama and Minnesota and discovered that the FBI techniques could not distinguish batches of lead produced months apart. They also discovered that differences existed within single batches. Their research was published in Forensic Science International in July 2002.

Although he still defended the technique, the director of the FBI Laboratory requested that the National Research Council (NRC) of the National Academy of Sciences review CBLA. In February 2004, the NRC report, titled Forensic Analysis: Weighing Bullet Lead Evidence, confirmed that only extremely limited claims could be made about the relationship between bullets based on CBLA. Given the NRC findings, a New Jersey appeals court overturned Behm’s conviction in March 2005. The results of the NRC study have obvious implications for many other cases as well.

In an article titled “Forensic Significance of Bullet Lead Compositions,” which appeared in the Journal of Forensic Sciences in March 2005, FBI research chemists Robert D. Koons and JoAnn Buscaglia argued that “compositional comparison of bullet lead provides a reliable, highly significant point of evidentiary comparison of potential sources of crime-related bullets.” In September of that year, however, the FBI announced that it would no longer use CBLA. (In a curious subsequent development, Tobin and a member of the NRC committee, Clifford Spiegelman, suggested that a reanalysis of the bullet fragments from the Kennedy assassination might be in order.)

An article published in New Scientist in April 2002, quoted Tobin as saying of the interpretation of bullet data based on CBLA, “It offended me as a scientist.” In fact, Tobin has a long record as a critic of FBI procedures he regards as bad science and of testimonial practices he regards as unwarranted by the scientific data. To complain about testimony that unreasonably goes beyond what the data can support is to respond equally to the demands of science and the demands of ethics. It is a feature of commonsense justice that the punishment should fit the crime, and a basic requirement of that, in turn, is that the people who are punished should be guilty. Violating that requirement is both bad science and bad ethics.

Joyce Gilchrist’s Tainted Evidence

Is it enough that the accused be guilty of some crime, or does it have to be the one in question? If the accused is guilty of the crime in question, does it matter whether the evidence actually shows that? The belief that one can convict the guilty by tweaking the evidence a little, or shading one’s testimony a bit, is among the most common sources of unethical (and, often enough, criminal) behavior on the part of forensic scientists. The cautionary tale of former Oklahoma City police Department forensic scientist Joyce Gilchrist probably falls into this category.

In May 2007, Curtis Edward McCarty, who was facing his third trial for a 1982 murder, was freed as the result of the improper handling and representation of hair evidence by Gilchrist, who apparently had tried to frame McCarty. The judge dismissed the charge despite her belief that McCarty was probably not completely innocent. This was merely the latest in a series of episodes involving Gilchrist.

Questions about the integrity of Gilchrist’s work began as early as January 1987, when a Kansas City colleague, John Wilson, complained about her to the Southwestern Association of Forensic Scientists, without result. In 1998, Robert Miller was exonerated after he had been convicted a decade earlier based in part on Gilchrist’s testimony regarding blood, semen, and hair evidence. In 1999, Gilchrist was criticized by a judge for having given false testimony (regarding semen evidence) in the rape/murder trial of Alfred Brian Mitchell in 1992. In the spring of 2000, Jeffrey Todd Pierce was ordered released after he had served a decade and a half for a rape he did not commit; he had been convicted based on Gilchrist’s testimony. In January 2001, Gilchrist was criticized for the various judicial reprimands and professional critiques her work had received. In August 2001, doubts were raised about the guilt of Malcolm Rent Johnson, who had been executed for a 1981 rape and murder; Johnson was convicted based on Gilchrist’s testimony.

A month later, in September 2001, Gilchrist was finally fired, after years of reputedly shoddy forensics work, including both mishandling and misrepresentation of evidence, on many cases in addition to those noted above. The world of criminal justice contains innumerable isolated instances of perverse idealism, self-serving cynicism, and simple incompetence, but Gilchrist is one of the most striking cases of flagrant disregard for ethics in the forensics community. Was she genuinely convinced of the guilt of those against whom she testified? (She was certainly persuasive to juries.) Was she cynically distorting her testimony, and the evidence, to help prosecutors gain convictions, or was she just incompetent?

Ethics of Competence

One may well agree with forensics ethicist Peter D. Barnett’s remark that “there is a certain baseline level of competence that every criminalist is expected to understand, and there are certain procedures and protocols that are so fundamental to the practice of criminalistics that failure to follow them is evidence of gross incompetence or malfeasance, which is unethical.” As Barnett himself notes, however, “in the practice of forensic science, the disparate educational and experiential backgrounds of workers in the field make determination of a baseline level of competence relatively difficult.”

This is a problem throughout the American criminal justice system. In June 2007, all sergeants in the New Orleans Police Department were required to attend a four-day seminar to learn how to improve their (and their subordinates’) writing of police reports. This was part of an attempt to smooth out conflicts between the department and the New Orleans district attorney’s office, which claimed that part of its difficulty in prosecuting criminals stemmed from “incomplete or vague reports” by officers. More generally, criminalists frequently lament that frontline officers are not more skilled in observing, protecting, collecting, and preserving crime scene evidence.

One certainly can (in theory) impose reasonable expectations about competence and development in forensic science. However, that is not made easy by the variety of educational backgrounds and practical experience of the people who actually work in the field. In an unflattering assessment published in 2005, Jane Campbell Moriarty and Michael J. Saks bluntly asserted that “in the forensic sciences . . . 96 percent of practitioners hold bachelor’s degrees or less.” They went on to note:

Most forensic “scientists” have little understanding of scientific methodology, do not design or conduct research (and do not know how to), often have not read the serious scientific literature beginning to emerge in their fields. . . . Scientific findings relevant to a given forensic science often are ignored in the conduct of everyday casework.

Moreover, as with the difficulty in defining the qualifications for expert testimony, the fact that crime fighting is not a natural kind of expertise has an impact. Almost any expert might be relevant to a criminal case, depending on circumstances. Given the diverse forms of knowledge relevant to the application of science to crime solving, and to the providing of suitable expert testimony, it may be that the only truly unifying factor is the application of the so-called scientific method, broadly understood as intellectual integrity—the determined effort, as physicist Richard P. Feynman put it, not to fool oneself (or others).

What is impressive about the case of William Tobin is his determination to ensure that his colleagues (or former colleagues) not testify to more than the data warrant, both out of scientific integrity and out of fairness to those whose lives are affected by what scientists say. What is appalling about the case of Joyce Gilchrist is the stubbornness of her effort to resist correction by colleagues or even by the seemingly obvious limits of the evidence itself. Sometimes the individual needs to correct the group, by exposing a bogus or complacent consensus; sometimes the group needs to correct the individual, by identifying willful deception or self-centered fantasy. Unfortunately, no formula exists to guarantee the right result, and that is why ethics remains a constant challenge to conscientious souls.

Ethical dilemmas in forensics

Related Information

  • American Academy of Forensic Sciences (AAFS)
  • American Society of Crime Laboratory Directors (ASCLD)
  • Brain-wave scanners
  • Criminal personality profiling
  • DNA database controversies
  • Ethics of DNA analysis
  • Expert witnesses in trials
  • Forensic journalism
  • Innocence Project
  • Interrogation in criminal investigations
  • Training and licensing of forensic professionals
  • Truth serum in interrogation

Last reviewed: October 2016

Bibliography

Barnett, Peter D. Ethics in Forensic Science: Professional Standards for the Practice of Criminalistics. Boca Raton: CRC, 2001. Print.

Inman, Keith, and Norah Rudin. Principles and Practice of Criminalistics: The Profession of Forensic Science. Boca Raton: CRC, 2001. Print.

Lucas, Douglas M. “The Ethical Responsibilities of the Forensic Scientist: Exploring the Limits.” Journal of Forensic Sciences 34 (1989): 719–29. Print.

Macklin, Ruth. “Ethics and Value Bias in the Forensic Sciences.” Journal of Forensic Sciences 42 (1997): 1203–206. Print.

Moriarty, Jane Campbell, and Michael J. Saks. “Forensic Science: Grand Goals, Tragic Flaws, and Judicial Gatekeeping.” Judges’ Journal 44.4 (2005): 16–33. Print.

Peterson, Joseph L., and John E. Murdock. “Forensic Science Ethics: Developing an Integrated System of Support and Enforcement.” Journal of Forensic Sciences 34 (1989): 749–62. Print.

Derived from: “Ethics.” Forensic Science. Salem Press. 2009.