Forensic Terminology

Here, I am going to mention the common terms used in Forensic Science. These terms are useful to understand the forensic science reports and to use them appropriately in your career:

Accused :- A person charged with a criminal offense. He is still not convicted of the crime.

Suspect:- Person suspected of committing a crime. There can be one or more suspects in a crime or criminal activity. However, few of them can be accused or convicted as criminal.

Culprit:- One who is found guilty of an offence after the investigation. He/She is also called as the criminal, perpetrator or offender.

Corpus Delicti – The essential body of facts that suggest a crime has occurred. From the Latin ‘body of crime’. All the parts of the crime scene are considered as corpus delicti.

Criminal Profiling –The analysis of the crime scene and crime patterns to assign relevant characteristics to a perpetrator in order to aid law enforcement in narrowing the field of suspects.

Crime Scene Staging – The alteration or manipulation of a crime scene in order to reduce its evidentiary value or to misguide the investigator.

Acquittal- A courtroom verdict in which a criminal defendant has not been found 

guilty. 

Evidence – Any items, in any state of matter or in any form encountered at the scene of crime and are included in a legal investigation for the jury’s or judge’s consideration in the determination of an individual’s guilt or innocence.

Circumstantial Evidence – Evidence from which a logical conclusion of a fact may be drawn.

Testimonial Evidence - statements or the spoken word from the victim(s) or witness(es).

Expert Witness – An individual with a specialized knowledge of a certain field that can assist in the understanding of complicated information or offer an expert opinion in the court of law. Example: Forensic Expert, Ballistic Expert etc.

Impression Evidence – The evidence left by anything that leaves a kind of impression at the scene or on an item, such as footprints, tire tracks, toolmarks, bite marks, fingerprints etc.

Indent – An impression left on paper caused by the force from a pen tip.

Trace Evidence – Minute pieces of evidence found at the crime scene, including fibre, hair, glass, seed, and soil.

PERK - The Physical Evidence Recovery Kit, or PERK, is a kit used to collect evidence. 

Signature Crime – A crime scene bearing the individual ‘stamp’ of a particular offender. It is not a physical stamp, however a particular pattern opted by the criminal or a particular symbol left at the crime scene.

Serial Killer – An individual who has murdered three or more people with a cooling-off period in between. This cooling off period can be in days or months.

CODIS – The Combined DNA Index System, the FBI database of genetic information

NDNAD – National DNA Database, the UK’s database of DNA profiles

IBIS—Integrated Ballistics Information System—a database used for acquiring, storing, and analyzing images of bullets and cartridge casings.

Exemplar—representative item usually in undamaged or less damaged condition to which a damaged item can be compared.

Oblique lighting—lighting cast at angle almost parallel with an object to show detail by creating shadows. The light at any angle other than 90 degree is often called as oblique light.

Point of origin—three dimensional point or area from which the blood that produced a bloodstain originated; determined by projecting angles of impact or well-defined bloodstains back to an axis constructed through the point or area of convergence. It is also used for fire in cases of arson.

AFIS—Automated Fingerprint Identification System

Back spatter—blood directed back toward the source of energy or force that caused the spatter; often associated with entrance gunshot wounds.

Castoff pattern—bloodstain pattern created when blood is released or thrown from a blood-bearing object in motion.

Drip pattern—bloodstain pattern resulting from blood dripping into blood.

Expirated blood—blood propelled from the nose, mouth, or a wound as a result of air pressure and/or air flow.

Impact spatter—bloodstain pattern created when blood receives a blow or force resulting in the random dispersion of smaller drops.

Medium velocity impact spatter—bloodstains produced when a blood source has been subjected to a medium velocity force (5-25 feet per second); beating usually produces this type of spatter .

Skeleton bloodstain—bloodstain consisting only of an outer periphery after the central  area is removed by wiping when the liquid was partially dry.

Junk DNA—the discovery that much of the DNA in every cell was repeated sequence DNA that doesn’t code for proteins and led to speculation that the repeat sequence DNA had no function.

Incendiary fire—fire intentionally caused by human activity.

Exsanguination—bleeding to death 

High velocity impact spatter—bloodstain pattern caused by a high velocity force or impact of approximately 100 feet or more per second, such as the force produced by a gunshot; the spatter is characterized by a mist-like dispersion; most mist-like droplets are usually 0.1 mm or smaller.

Direct evidence—information that established fact, for example, an eyewitness’ testimony that the defendant fired the fatal shot.

Blow flies—large metallic looking flies often attracted to a dead body immediately after death.

Maggots - The larvae of flies and other insects that live on rotting food.

Rigor mortis - The stiffening of the body muscles after death.

Algor Mortis – The reduction in body temperature after death.

Hypostasis (Livor Mortis) – Also known as lividity. The pooling of blood at the lowest parts of the body. Usually commences between six and eight hours after death has occurred.

Chain of Custody/Evidence- A continuous succession of persons responsible for the evidence with the purpose to ensure there is neither alteration nor loss of evidence: the documentation of the chain of custody is a record of times, places, and persons who have been responsible for the evidence. Transfers should be kept to a minimum and when transfers are made, they should be documented carefully. All transfers of custody of evidence must be logged with: the name of the persons transferring custody-the name of the persons receiving custody-and the date and time of each transfer: the documentation may be attached to the evidence envelope. 

Strangulation - The condition of having respiration stopped by compression of the air passage.

Strangling is compression of the neck that may lead to unconsciousness or death by causing an increasingly hypoxic state in the brain.

Hanging—Suspension from a cord wound around the neck.

Ligature strangulation—Strangulation without suspension using some form of cord-like object called a garrote.

Manual strangulation—Strangulation using the fingers or other extremity

Asphyxia – Death caused by suffocation as a result of the lack of oxygen and increase of carbon dioxide in the blood. Also known as apnoea.

Electrocution - Death brought about by electricity.

Hypothermia - This situation occurs when the core temperature of one's body falls below normal. It is the failure of the body to maintain adequate production of heat under conditions of extreme cold.

Abrasion – An injury to the skin that removes the epithelial layer.

Contusion – A soft hemorrhage from a blunt trauma.

Laceration – The splitting or tearing of the skin.

Manner of Death – The way in which death was caused; homicide, suicide, accidental, natural, or undetermined.

Homicide – Murder, a death caused by another person.

Suicide – a death caused by same person (killing of self).

Hypoxia – Decrease in oxygen to the brain.

Equivocal death—manner of death (homicide, suicide, accident) remains undetermined after a complete investigation.

Cadaveric Spasm – The sudden rigidity of the muscles immediately after death.

Mechanism of death—abnormality produced by the cause of death which is incompatible with life.

Facial Reconstruction - Reconstruction of unidentified human remains is done by modeling clay, representing muscle, tissue and skin, over the skull. On the forehead, margins of the eyes, cheekbones, bridge of the nose, above the lips, and the chin, facial shape is closely related to skull contour. However, the shape of the eyes and eyelids, the tip of the nose, and the lips cannot be predicted from the skull, and these are important features in facial recognition. Advances in 3-D computer modeling are aiding in and may soon replace a sculpted facial reconstruction.