Criminalistics and Forensic Science Principles

Comprehensive vocabulary flashcards covering the introductory concepts, foundational principles, scientific debates, and analytical disciplines in criminalistics and forensic science based on Leiden University lecture handouts.

Criminalistics (Berger, 2010)

The discipline defined as 'terugredeneren' (reasoning backwards from the physical trace to the source and the event).

Criminalistics (Kirk, 1963)

The branch of science defined concisely by Paul L. Kirk as 'the science of individualization.'

Criminalistics (American Board of Criminalistics)

That profession and scientific discipline directed to the recognition, identification, individualization, and evaluation of physical evidence by application of the physical and natural sciences to law-sciences matters.

Criminalistics (California Association of Criminalists)

That professional occupation concerned with the scientific analysis and examination of physical evidence, its interpretation, and its presentation in court.

Forensic Science (American Academy of Forensic Sciences, 2003)

The application of scientific principles and technological practices for the purposes of justice in the study and resolution of criminal, civil, and regulatory issues.

Forensic Science (Sensabaugh, 1997)

A systematic endeavor to describe how events of legal concern have happened based on observation, hypothesis formation, and experiment.

Criminology

The scientific study of the causes, correction, and prevention of crime, functioning as a subfield within the broader discipline of sociology.

Netherlands Forensic Institute (NFI)

An independent forensic services agency in the Netherlands with no investigative or supervisory powers, dedicated to casework ($70\%$), research and development ($15\%$), and knowledge management ($15\%$).

Locard's Exchange Principle (Edmond Locard, 1923)

A foundational forensic axiom stating that 'every contact leaves a trace' ('nul ne peut agir avec l\'intensité que suppose l\'action criminelle sans laisser des marques multiples dans son passage').

Divisibility of Matter (Inman & Rudin, 2002)

The principle stating that matter divides into smaller components when sufficient force is applied; these parts acquire traits produced by the division process while retaining the physico-chemical properties of the original object.

Identification (Inman & Rudin, 2002)

The forensic process focused on determining the chemical or physical composition and nature of a trace (e.g., determining a substance is cocaine).

Classification (Inman & Rudin, 2002)

The forensic process of assigning a trace to a particular class, category, or type of item (such as identifying hair or fiber types).

Individualization (Inman & Rudin, 2002)

The forensic determination of a unique, single source for a given trace to the exclusion of all other possible sources (e.g., fingerprint matching).

Association (Inman & Rudin, 2002)

The process of inferring that a relevant physical contact took place between two objects or persons based on mutually transferred traces (e.g., fibers, glass, or tool marks).

Reconstruction (Inman & Rudin, 2002)

The holistic process of determining how an incident occurred by establishing the nature, sequence, location, and trajectory of events in time and space.

Bertillonage (Anthropometry)

An identification system devised by Alphonse Bertillon in the late 19th century based on standardized physical body measurements (e.g., body length, skull length/width, right ear size, left foot length), first identifying a recidivist in 1883.

Class Characteristics (Thornton & Peterson, 2003)

General properties that separate a group of objects from the broader universe of objects, used to screen items by eliminating non-matching members, but inherently incapable of proving uniqueness.

Individual Characteristics (Thornton & Peterson, 2003)

Exceptional properties or unique arrangements/ensembles of traits (such as random striations on a fired bullet) that serve to distinguish an object from all others.

Comparison Microscope

An optical apparatus consisting of two synchronized microscopes joined by an optical bridge, allowing side-by-side comparison of microscopic surface striations on bullets, cartridge cases, or toolmarks.

Minutiae

Local friction ridge details in a fingerprint pattern—such as ridge endings, bifurcations, double bifurcations, and double endings—used for identification and individualization comparisons.

Positivity Doctrine (IAI Resolution 1979 VII)

A mandatory policy adopted in 1979 (revised 1980, rescinded 2010) by the International Association for Identification, deeming it professional misconduct for friction ridge examiners to report probable, possible, or qualified identifications instead of absolute certainty.

Twelve Minutiae Rule (Locard Rule, 1920)

An empirical rule originating from Edmond Locard asserting that finding 12 matching minutiae with no unexplained differences is sufficient to establish definitive individualization.

Leap of Faith (Stoney, 1991)

David Stoney's observation that fingerprint examiners observe increasing points of similarity until they undergo a subjective transition to certainty of identity rather than providing objective scientific proof.

Categorical Conclusion

A definitive, binary conclusion (yes or no) asserting that a trace unequivocally originates from a specific source, characteristic of classical fingerprint reporting but rejected by modern logic as overreaching limited empirical data.

Probabilistic Conclusion

A conclusion framed using degrees of uncertainty or statistical evaluation (such as random match probabilities in DNA profiling, or qualitative likelihood frameworks), acknowledging that complete certainty cannot be scientifically demonstrated.

Deduction vs. Induction (C.S. Peirce)

In logic: deduction proceeds from a general rule through a specific case to an inevitable categorical result; induction proceeds from specific cases and results to generalize a probabilistic rule.

Forensic Pathology

A forensic subdiscipline using external and internal autopsies to determine cause of death, time of death, injury mechanisms, and manner of death.

Forensic Toxicology

The analysis of biological matrices (blood, urine, bile, saliva, organs, stomach contents) using chromatographic and spectroscopic methods to identify and quantify toxic agents and drugs in relation to death or impairment.

Gunshot Residue (GSR / FDR)

Particulate matter composed of primer and propellant elements (typically containing lead, barium, and antimony) collected using adhesive stubs and analyzed using SEM-EDX and chemical tests.