Forensic Science Chapters 1 and 2

Abductive reasoning

Most commonly used reasoning based on gathering known information to come up with the simplest and most likely explanation.

Admissibility

A legal rule that decides whether a court can allow a piece of information, object, or testimony during trial.

Circumstantial evidence

Indirect proof that suggests a fact is true by connecting surrounding details and clues rather than showing it directly.

Daubert standard

Rule where the trial judge determines if scientific evidence is relevant and the expert witness is qualified.

Daubert trilogy

A group of 3 U.S. Supreme Court cases setting modern rules for whether an expert witness can testify in federal court.

Deductive reasoning

Reasoning compared to algebra and mathematical logic.

Direct evidence

Information that proves or verifies directly without further information, such as eyewitness testimony or video recordings.

Exclusive evidence

Proof pointing to only one conclusion or party, leaving no other explanation or alternative overlap.

Exculpatory evidence

Evidence tending to clear someone of guilt, blame, or legal responsibility.

Federal Rules of Evidence

The official rules for what proof can be shown in a federal court.

Frye standard

Legal test requiring scientific techniques or methods to be generally accepted by the relevant scientific community.

Inclusive evidence

Evidence that includes a person or object within a group of possibilities because their characteristics match.

Inculpatory evidence

Evidence or material that shows or tends to show a person's guilt or involvement in a crime.

Inductive reasoning

Uses existing data to make predictions and generalizations.

Locard's exchange principle

States that any contact or interaction between two objects or people leaves some sort of evidence behind.

Opinion evidence

Testimony based on judgment, inference, or belief rather than direct personal knowledge.

Physical evidence

Raw material needed by forensic scientists.

Rules of evidence

Guidelines that decide what information a judge or jury can hear or see during a court trial.

Testimonial evidence

Spoken or written statements made by a witness under oath.

Transfer evidence

Any substance or particle exchanged between people, objects, or a crime scene during an interaction.

DNA Evidence & Scene Linkage

Finding a person's DNA on another links them to the scene generally, but lacks a 100% test for the exact specific field without corroborating evidence.

Exclusionary Federal Rules

Evidence cannot be entered or used if it violates the defendant's constitutional rights.

Frye vs. Daubert Standards

Frye relies on general scientific acceptance, whereas Daubert requires the judge to act as a gatekeeper testing reliability.

Daubert Trilogy Decision

Trial judges determine if expert testimony is reliable, relevant, and broadly applicable beyond just hard science.

Categorizing a Bloody Gun

Classified as physical, inclusive, inculpatory, and circumstantial evidence depending on context and connection to the crime.

Bloodstain Pattern Classification

Circumstantial evidence because it requires logical reasoning with surrounding clues and facts to prove a violent crime.

Medical Diagnosis Reasoning

Doctors primarily use abductive reasoning, using known symptoms to make the most likely prediction.

Adjudicated

A case that has been settled.

Burden of Proof

The prosecution must prove without a reasonable doubt that the defendant is guilty.

Civil Law

Legal cases between individuals and private parties, such as lawsuits.

Criminal Law

A system of rules defining illegal actions and setting punishments for people who break them.

Defendant

A person or group accused of a crime or sued in a court of law.

Felony

A serious crime carrying a potential prison sentence of more than one year or the death penalty.

Jurisdiction

A geographical area over which law enforcement or a legal entity can exercise authority.

Misdemeanor

A minor criminal offense less serious than a felony, usually involving minor fines or short jail time.

Plea Bargaining

Negotiation between defendant and prosecutor where the defendant pleads guilty for a lighter sentence.

Probable Cause

When law enforcement has enough facts and evidence to suspect a person committed a crime.

Prosecution

The party that files criminal charges against a defendant.

Trier of Fact

A jury or judge that decides the fate and guilt of the defendant in a case.

Breath Test & Probable Cause

Breath test results combined with intoxication signs provide probable cause for police to investigate further or arrest.

Innocence & Burden of Proof

Because defendants are presumed innocent, the prosecution must prove guilt beyond a reasonable doubt or fail to convict.

Fourth Amendment

Constitutional amendment protecting individuals against unreasonable searches and seizures and requiring warrants based on probable cause.

Fifth Amendment

Constitutional amendment guaranteeing rights including protection against self-incrimination, double jeopardy, and guaranteeing due process of law.

Sixth Amendment

Constitutional amendment guaranteeing the right to a speedy and public trial by an impartial jury, legal counsel, and witness confrontation.

Seventh Amendment

Constitutional amendment guaranteeing the right to a jury trial in civil lawsuits involving federal matters.

Eighth Amendment

Constitutional amendment prohibiting excessive bail, excessive fines, and cruel and unusual punishment.

Fourteenth Amendment

Constitutional amendment guaranteeing equal protection under the law and due process, extending constitutional rights to state actions.

Primary crime scene

The specific location where the initial criminal act took place.

Secondary crime scene

A location associated with events following the initial offense, such as a burial site or vehicle used in transport.

Macroscopic crime scene

The large-scale environment of an investigation, encompassing an entire building or lot.

Microscopic crime scene

A specific, smaller area or individual room within a larger investigation site.

First responder

The individual who initially arrives at a scene and prioritizes emergency assistance, scene safety, and preservation.

Walk-through

An initial inspection conducted by investigators to define scene scope and identify critical areas before detailed processing.

Elimination samples

Reference materials, such as fingerprints or biological samples, collected from personnel who entered a scene to rule them out.

Control samples

Unaffected materials gathered from a scene to establish a baseline for comparative laboratory analysis.

Triangulation method

A scene measurement technique that fixes the location of evidence relative to two known reference points.

Baseline method

A coordinate system measuring evidence location along a line between two fixed points and at right angles to that line.

Polar coordinates method

A mapping technique measuring distance and angles from a fixed point using a transit or compass.

3D forensic mapping

A digital scene recording technique utilizing light detection and ranging technology to construct three-dimensional visual models.

Line search pattern

A systematic search layout where searchers move side-by-side in parallel straight lines across outdoor terrain.

Grid search pattern

A thorough search method covering a scene in overlapping, perpendicular paths.

Zone search pattern

A search approach where a scene is partitioned into smaller defined sections assigned to specific team members.

Spiral search pattern

A search route moving in expanding or contracting circles, best suited for areas lacking physical barriers.

Paper packaging for biological evidence

Breathable containers used for storing moist biological samples to permit drying and prevent decay.