Introduction to Forensic Science and Crime Scene Investigation

Comprehensive vocabulary flashcards covering the organization of crime laboratories, legal standards of evidence admissibility, processing and documenting the crime scene, key historical contributors, national forensic databases, and bloodstain pattern reconstruction.

Forensic Science

The application of science to law.

Locard's Exchange Principle

The principle stating that whenever a person comes into contact with an object or another person, a cross-transfer of materials occurs, enabling a criminal to be connected to a crime by dust particles.

Anthropometry

A systematic identification method developed by Alphonse Bertillon that uses a series of precise body measurements to identify individuals.

Mathieu Orfila

A pioneer of forensic toxicology recognized for detecting poisons and their physiological effects on animals.

Francis Galton

The scientist who undertook the first definitive study of fingerprints and established a methodology for classifying them for filing and personal identification.

Leone Lattes

The investigator who devised a procedure to determine blood groups ($\text{A}$, $\text{B}$, $\text{AB}$, and $\text{O}$) from dried bloodstains.

Calvin Goddard

The firearms examiner who refined the technique of determining whether a particular gun fired a bullet by utilizing the comparison microscope.

Albert S. Osborn

The pioneer who established the fundamental principles of document examination, enabling questioned documents to be accepted as scientific evidence.

Frye Standard

A standard of admissibility established in Frye v. U.S. requiring that a questioned scientific procedure, technique, or principle must be generally accepted by a meaningful segment of the relevant scientific community.

Daubert Standard

Guidelines established in Daubert v. Merrell Dow Pharmaceuticals, Inc. asserting that the trial judge acts as a gatekeeper to ensure an expert's testimony is both scientifically reliable and relevant.

Coppolino v. State

A court ruling upholding the admissibility of novel scientific tests for a succinylcholine chloride overdose, determining that homicide is not tolerated simply because medical literature has not yet caught up.

Expert Witness

An individual whom the court determines possesses knowledge relevant to the trial that is not expected of an average layperson, demonstrated through education, experience, or specialized training.

Bullcoming v. New Mexico

A court ruling establishing that surrogate testimony or fill-in scientists cannot substitute for the original analyst who performed the testing, preserving the right to cross-examination.

Melendez-Diaz v. Massachusetts

A Supreme Court case ruling that forensic certificates or reports cannot be introduced without providing the defense the opportunity to cross-examine the testing analyst in person.

Physical Science Unit

A basic crime laboratory unit staffed by chemists, physicists, and geologists that identifies drugs, analyzes soil and minerals, and examines trace physical evidence.

Voiceprint Analysis

A specialized technique using a sound spectrograph to create a visual display of speech patterns to tie telephoned threats or recorded messages to a specific suspect.

Forensic Odontology

A specialized forensic discipline using teeth, due to their hard enamel, to identify otherwise unidentifiable victims and analyze bitemarks.

Physical Evidence

Any object that can establish that a crime has or has not been committed, or can link a crime to its victim or its perpetrator.

Rough Sketch

A draft representation of all essential information and measurements of a crime scene, drawn on-site during the early investigation phase.

Finished Sketch

A precise rendering of a crime scene drawn to scale, often completed using computer-aided drafting (CAD).

Strip or Line Search

A search pattern where one or two investigators start at one boundary and walk straight across to the other boundary, then shift slightly along the border and walk parallel to the initial path.

Grid Search

A thorough search pattern conducted by two people performing line searches along adjacent boundaries using perpendicular lines.

Quadrant or Zone Search

A search pattern where the scene is divided into zones or quadrants with assigned team members, best suited for large areas and points of criminal entry and exit.

Druggist Fold

A folded-paper packaging method used to secure small amounts of trace physical evidence.

Chain of Custody

A documented continuity of possession listing all individuals who come into possession of an item of evidence, authenticated by collector initials, dates, and evidence seals.

Standard/Reference Sample

Physical evidence of known origin, such as hair from a suspect, collected to compare directly against questioned crime-scene evidence.

Buccal Swab

A swab of the inner cheek used to collect epithelial cells for determining an individual's DNA profile.

Substrate Control

Uncontaminated surface material collected close to an area where physical evidence was deposited, ensuring the background surface does not interfere with laboratory tests.

Mincey v. Arizona

A Supreme Court ruling declaring that a warrantless, multi-day search of drug dealer Rufus Mincey's residence following an officer shooting violated the Fourth Amendment, rendering the seized evidence inadmissible.

Michigan v. Tyler

A Supreme Court case ruling that while an initial search during a fire is permissible, warrantless reentries into a burnt business $4$, $7$, and $25\,\text{days}$ later are unconstitutional.

CODIS

The Combined DNA Index System, an FBI electronic database linking local, state, and federal DNA profiles across forensic, offender, and arrestee categories.

Rapid DNA

A fully automated process capable of generating DNA profiles from a buccal swab in $90\,\text{mins}$ or less for compatibility with CODIS searches.

Maryland v. King

A Supreme Court ruling establishing that collecting DNA samples from individuals arrested for serious offenses, prior to conviction, is permissible under the Fourth Amendment.

NIBIN

The National Integrated Ballistic Information Network, managed by the ATF, which utilizes the Integrated Ballistic Identification System (IBIS) to compare firearm markings on bullets and cartridge casings.

SICAR

Shoeprint Capture and Retrieval, a commercially maintained non-governmental database that compares and identifies footwear impressions using its Solemate and TreadMate modules.

Crime Scene Reconstruction

The method used to support a likely sequence of events at a crime scene through the observation and evaluation of physical evidence and statements made by involved individuals.

Satellite Stain

A small bloodstain originating during the formation of a parent stain as a result of blood impacting a surface.

Angle of Impact

The acute angle ($\alpha$), relative to the plane of a target, at which a blood drop strikes the target.

Impact Spatter

The most common bloodstain pattern, created when an external force is applied directly to liquid blood.

Forward Spatter

Blood drops projected outwards in the direction of travel when a projectile creates an exit wound.

Back Spatter

Also called blow-back spatter, blood drops projected backwards toward the source of impact when a projectile produces an entrance wound.