True Crime Podcast Glossary: Terms Every Listener Should Know

True crime podcasts are full of terminology that appears without explanation — legal concepts, forensic science terms, investigative vocabulary, and genre-specific language that new listeners encounter constantly. This glossary covers the most important terms you'll encounter across the genre.

A

Alibi — Evidence or testimony that a suspect was elsewhere at the time a crime was committed. A verified alibi excludes someone from suspicion; an unverified alibi requires further investigation.

Autopsy — A medical examination of a body, performed by a pathologist, to determine cause and manner of death. Autopsies generate reports that become key pieces of evidence in homicide investigations. The forensic pathologist who conducts the autopsy is often called as a witness at trial.

Arraignment — The first court appearance after charges are filed, at which the defendant is formally notified of the charges and enters a plea (guilty, not guilty, or no contest).

B

Ballistics — The science of firearms and projectiles, including the examination of bullets, cartridge cases, and firearms to connect weapons to crimes. Ballistics analysis can determine whether a specific weapon fired specific bullets.

Brady Violation — A breach of the Supreme Court's Brady v. Maryland ruling, which requires prosecutors to disclose exculpatory evidence (evidence that might help the defence) to defence attorneys. Brady violations are a documented cause of wrongful convictions.

Binge-Worthy — In the true crime podcast context, a show that incentivises listening to multiple episodes in sequence rather than one at a time. Serial, Dirty John, and Teacher's Pet are all binge-worthy in the sense that narrative structure creates strong episode-to-episode momentum.

C

Chain of Custody — The documented record of everyone who handled a piece of physical evidence, from the crime scene to the courtroom. A broken chain of custody — evidence that cannot be proven to have remained uncontaminated — can make physical evidence inadmissible.

Cold Case — A criminal investigation suspended due to lack of leads but not formally closed. Cold cases can be reopened when new evidence emerges, usually new witnesses, new forensic technology, or renewed investigative attention from podcasters, journalists, or advocacy groups.

CODIS — Combined DNA Index System. The FBI's national database of DNA profiles from convicted offenders, arrestees, and crime scenes. A DNA profile from a crime scene that "hits" in CODIS identifies a suspect who has previously been arrested or convicted.

Contempt of Court — Legal restrictions on what can be published or broadcast about ongoing criminal proceedings. UK contempt of court laws are significantly more restrictive than US First Amendment protections, which is one reason British true crime podcasting has historically focused more on historical cases.

Coroner — A government official responsible for investigating deaths that may be unnatural, violent, or mysterious. In the US, coroners are often elected and may not be medically qualified; medical examiners are medically qualified pathologists. The distinction matters in podcast discussions because the quality of death investigations varies significantly.

CSI Effect — The documented phenomenon whereby jurors, having consumed forensic science as entertainment (through shows like CSI), have unrealistically high expectations of forensic evidence. This can work against prosecution (jurors expect DNA evidence that may not exist) or in its favour (jurors overweight forensic evidence that may be flawed).

D

DNA Genealogy / Genetic Genealogy — A technique for identifying unknown suspects by comparing crime scene DNA against genealogy databases (like 23andMe or GEDmatch). By identifying relatives of the unknown contributor, investigators can work toward identifying the contributor themselves. Famously used to identify the Golden State Killer in 2018.

Double Jeopardy — The legal principle that a person cannot be tried twice for the same crime after acquittal or conviction. In the US, this is a constitutional protection under the Fifth Amendment. In the UK, the rule was modified by the Criminal Justice Act 2003, allowing retrial in serious cases where new and compelling evidence emerges — which has enabled several high-profile cold case convictions.

E

Exculpatory Evidence — Evidence that tends to show a defendant is not guilty. Brady v. Maryland requires prosecutors to share exculpatory evidence with the defence.

Exoneration — The formal clearing of someone who was wrongly convicted. DNA exonerations (where DNA evidence establishes innocence) have freed more than 375 people in the US since 1989, according to the Innocence Project.

F

False Confession — A confession to a crime the confessor did not commit. False confessions are more common than intuition suggests — they contribute to approximately 25% of DNA exonerations. They occur under conditions including prolonged interrogation, sleep deprivation, psychological vulnerability, and coercive questioning techniques.

FOIA (Freedom of Information Act) — US legislation allowing individuals to request government documents. Investigative journalists and podcasters regularly use FOIA requests to access police records, autopsy reports, and court documents. UK equivalent: Freedom of Information Act 2000.

Forensic Anthropology — The application of physical anthropology to legal contexts, including the identification of human skeletal remains. Used when bodies have decomposed to the point where conventional identification is impossible.

Forensic Pathology — The subspecialty of pathology concerned with determining the cause and manner of death in deaths that are unnatural, sudden, or suspicious. The forensic pathologist performs autopsies and testifies in court.

G

Grand Jury — A US legal institution in which a group of citizens review evidence to determine whether there is sufficient probable cause to charge someone with a crime. Grand jury proceedings are secret; the defendant has no right to appear or cross-examine.

H

Homicide — The killing of one person by another. Not all homicide is criminal: justifiable homicide (self-defence, for example) and excusable homicide are legal categories. True crime typically focuses on criminal homicide — murder and manslaughter.

I

Innocence Project — A US non-profit organisation that uses DNA evidence to exonerate wrongly convicted individuals. Founded in 1992 at Cardozo School of Law, it has contributed to over 375 exonerations and regularly features in true crime podcast discussions of wrongful conviction.

Inquest — In the UK, a formal public inquiry conducted by a coroner into the cause of death in cases that are sudden, unnatural, or suspicious. Inquests are not criminal proceedings — they cannot result in a conviction — but their findings can contribute to subsequent criminal investigations.

J

JDAI (Juvenile Detention Alternatives Initiative) — A programme relevant to some true crime cases involving juvenile offenders, aimed at reducing unnecessary detention of young people.

Jilted Lover Theory — The common investigative hypothesis, in cases of intimate partner violence, that a romantic partner motivated by jealousy or rejection is responsible. Often correct; sometimes wrong in ways that derail investigations.

L

Luminol — A chemical that reacts with the iron in haemoglobin to produce a blue glow under ultraviolet light, even in blood traces that have been cleaned. Luminol testing can detect blood that's been removed from a scene.

M

Manner of Death — The category of circumstances that caused a death: homicide, suicide, accident, natural causes, or undetermined. Distinct from cause of death (the medical mechanism — e.g., "gunshot wound to the head").

MMRV (Missing and Murdered Indigenous Women and Girls) — A crisis in Canada and the US involving disproportionate rates of violence, murder, and disappearance among Indigenous women. Central to several important Canadian true crime podcasts, including Missing & Murdered.

N

NamUs (National Missing and Unidentified Persons System) — A US government database containing information about missing persons and unidentified remains. A key resource for cold case investigators and the true crime community.

P

Plea Bargain — An agreement between a prosecutor and defendant in which the defendant pleads guilty (usually to a lesser charge or in exchange for a reduced sentence) in exchange for avoiding trial. The vast majority of US criminal cases — approximately 90% — are resolved through plea bargains rather than trial.

Probable Cause — The legal standard required for arrest, search, or seizure in US law: there must be reasonable grounds to believe a crime has been committed and that the person or location is connected to it.

R

Reid Technique — A police interrogation method involving psychological manipulation, including false evidence presentations and minimisation ("your partner probably did most of it — you just need to tell us what happened"). It is associated with false confessions and has been substantially abandoned in favour of more evidence-based approaches by many jurisdictions.

S

Serial Killer — A person who has killed three or more people, with a cooling-off period between murders. The cooling-off period distinguishes serial killers from mass murderers (multiple victims, single event) and spree killers (multiple victims, multiple locations, no cooling-off period).

Signature Behaviour — In criminal profiling, behaviours at a crime scene that go beyond what's necessary to commit the crime and reflect the offender's psychological needs. Distinct from MO (modus operandi), which is the practical method of committing the crime.

SIDS (Sudden Infant Death Syndrome) — The unexplained death of an apparently healthy infant, usually during sleep. Some historical SIDS cases have been re-examined as possible homicides; other alleged homicides have been identified as genuine SIDS. Getting this right requires careful forensic pathology.

T

Trace Evidence — Small physical materials that can be transferred between a perpetrator and a victim or scene, including fibres, hair, glass fragments, soil, and pollen. Trace evidence analysis is a key tool in forensic investigation.

True Bill — A grand jury's determination that there is sufficient evidence to proceed with criminal charges. The opposite — insufficient evidence — produces a "no bill."

V

VICAP (Violent Criminal Apprehension Program) — The FBI's national database for tracking serial violent crimes. Law enforcement agencies submit case information, and VICAP identifies patterns across jurisdictions. Critical for identifying serial killers who operate in multiple states.

W

Wrongful Conviction — A conviction of a person who was actually innocent of the crime. Documented causes include eyewitness misidentification, false confessions, informant testimony, ineffective assistance of counsel, prosecutorial misconduct, and flawed forensic evidence.

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