Forensic Science: Introduction & History Notes

Forensic science lies at the convergence of legal and scientific systems.
The law seeks certainty: who committed the crime and where, in the pursuit of justice.
Science, by contrast, can only establish the simplest facts and deal with probabilities, odds of an occurrence, etc.; it aims for greater understanding rather than absolute certainty.

Juries ultimately decide what odds are sufficient to convict someone of a crime.
This task is complicated by the increasing technical complexity of scientific evidence that juries must understand to reach a fair verdict.
Example: DNA evidence; 1985 marked a point where juries had to learn and understand DNA analysis.

1923 Frye Case established that the scientific community must determine what forensic evidence is based on good science and is allowable in court (the Frye standard/criterion).
The criminal justice system relies on the scientific community to provide accurate and objective results from scientific analysis.

Many disciplines contribute to forensics: medicine, chemistry, physics, psychology, anthropology, entomology, etc.
Forensic science has evolved into a variety of complex sub-specialties with expert specialists.
Question posed: What makes an “expert”?

Science has limitations in finding and analyzing evidence.
Juries are often unsatisfied if not all possible types of scientific data are presented; this can lead to excessive, useless, and expensive forensic testing.
A strong system of justice requires a strong partnership with forensic science.

To maintain high standards and acceptable practices, various organizations and agencies have been developed:
- AAFS: American Academy of Forensic Science
- ASCLD: American Society of Crime Lab Directors
- Department of Justice (DOJ)
- UN: United Nations

1.2 – Brief History of Forensic Science
Definition: The application of scientific methods and principles to the investigation of crimes and criminals.

Criminalistics: The science and profession dealing with the recognition, collection, identification, individualization, and interpretation of physical evidence, and the application of the natural sciences to law-science matters.

Early Romans & Greeks used natural-world understanding to deduce logical arguments related to criminal prosecutions ( BCE ).
Archimedes: “Father of forensic science.”
Quintilian: Roman attorney; purportedly demonstrated that a person was framing a blind man in the homicide of his mother (note: referenced here as a 10th-century example).
Sung T’ze: Published the first forensic textbook; reported how flies were used to detect blood on a harvest scythe used to kill a man (c. 1248 AD).

Mathieu Orfila — the father of forensic toxicology.
Calvin Goddard — used a comparison microscope to determine if a particular gun fired a bullet.
James Marsh — first to present a toxicology test to a courtroom and jury.
Sir William Herschel — used fingerprints on Indian Civil Service papers to verify identity for those who were illiterate.
Alphonse Bertillon — devised the first scientific system of personal identification in 1879 (Anthropometry).

Anthropometry: Bertillon’s systematic procedure of taking a series of body measurements to distinguish individuals.
This method was considered the most accurate until it was replaced by fingerprinting.
Term: ANTHROPOMETRY (Bertillon)

Alexandre Lacassagne — founded the first school to train people in forensic subfields; standardized practices; included blood pattern analysis and firearms examination.
Hans Gross — wrote the first treatise describing the application of scientific principles to criminal investigation.
Sir Edward Henry — developed a fingerprint classification system used worldwide.

Karl Landsteiner — discovered human blood groups and how to type them; ABO blood type is the most commonly used.
Edmond Locard — incorporated Gross’s principles into a workable crime laboratory.
Locard’s Exchange Principle: a criminal leaves something behind at a crime scene and also takes something away with them; evidence is transferred and exchanged between the crime scene and the criminal.

1924 – The first crime lab in the United States was formed with the Los Angeles Police Department.
1932 – Under J. Edgar Hoover, the FBI organized a national (federal) lab offering forensic services to all law enforcement agencies.
- The FBI lab consulted with business executives, manufacturers, and scientists to gain information.
- It is now the largest crime lab in the world.

The increasing number of crime laboratories is partly due to:
1) A surge in drug-related cases; drug specimens flooded laboratories due to accelerated drug abuse; 1960s marked a focus on detection and prosecution; a majority of crimes had some drug or alcohol connection.
2) The advent of DNA profiling; 1980s – DNA technology revolutionized personal identification of biological samples.

Modern crime labs require enhanced capabilities, state-of-the-art instrumentation, and adherence to best-known practices for evidence analysis.
Labs are subject to tighter controls and stricter standards, along with increasing caseloads.

Connections to broader themes and implications

Forensic science operates at the intersection of empirical evidence and legal standards; reliability, transparency, and admissibility depend on community consensus (e.g., Frye) and ongoing standard-setting.
The balance between providing comprehensive scientific data and avoiding over-testing is essential for fairness and cost-effective justice.
Locard’s Exchange Principle underpins many forensic techniques by highlighting the bidirectional transfer of evidence between crime scenes and suspects.
The historical shift from anthropometry to fingerprinting reflects the evolution toward more reliable, universally applicable identification methods.
DNA technology catalyzed a paradigm shift in personal identification, transforming how biological evidence is interpreted and presented in court.
Modern labs operate under tighter governance to ensure quality, accuracy, and ethics in forensic findings, given their impact on justice outcomes.