Any object that can establish that a crime has or has not been committed, or link an individual to a crime.
Chain of Custody
A list of all people who came into possesion of an item of evidence.
Standard Reference Sample
Physical evidence whose origin is known, such as blood or hair from a suspect.
Uncontaminated surface material close to an area where physical evidence has been posited.
A swab of the innter portion of the cheek; DNA sample
The process of determining a substances physical or chemical identity ex: drug analysis
The process of ascertaining whether two or more objects have a common origin.
Properties of evidence that can be attributed to a common source with an extremely high degree of certainty.
Properties of evidence that can be associated only with a group, not one thing.
Multiplying together the frequencies of independently occurring genetic markers.
An individual who investigates sudden, unnatural, unexplained, or violent deaths.
The medical dissection of and examination of a body to determine death.
Stiffening of body after death.
Settling of blood after death, the blood is most abundant in areas closest to the ground due to gravitational pull.
The behavior of a substance without altering compostion, how it appears.
The behaviorof a substance when it reacts orcombines with another substance. Chemical reactions
A property that is not dependent on the size of an object.
The bending of a light wave as it passes from one medium to another.
The ratio of the speed of light in a vacuum to its speed in a given substance.
A solid in which the constituent atoms have a regular arrangement.
Atoms are arranged in random disordered positions.
Two sheets of ordinary glass bonded together with a plastic film.
Glass strengthened by introducing stress through rapid cooling and heating.
Refractive index unit.
A crack in the glass that extends outward like a spoke of a wheel from where it was struck.
A crack in the glass that forms a rough ircle around the point of impact.
All things of substance, matter is composed of atoms and or molecules.
Cannot be broken down, it is the fundamental unit of compounds and molecules.
A table of elements arranged in a systematic fashion by atomic mass.
A pure substance composed of two or more elements
A condition or stage in the form of matter: solid, liquid, gas.
A physical change from the solid state directly into a gaseous state.
An analytical method for indentifying a substance by its selective absorption.
Any of several analytical techniques for sparating organic mixtures. There is a stationary and a mobile phase.
The decomposition of organic matter by heat.
To emit visible light when exposed to light of a shorter wavelength ultraviolet light.
A technique for separating molecules through migration on a support medium while under the influence of an electrical potential.
Colored light ranging from red to violet in the electromagnetic spectrum.
The distance between crests of adjacent waves.
The number of waves that pass a given point per second. Shorter wavelength means a higher frequency.
The entire range of radiation energy from the most energetic to the least energetic. The rainbow is the magnetic spectrum.
A high energy short wavelength form of electromagnetic radiation.
An acronym for light amplification by stimulated emission of radiation. The light is a beam of unison pulse.
A small packet of electromagnetic radiation energy. Each photon contains a unit of energy equal to the product of Planks Constant.
A device for isolating individual wavelengths for frequencies of light.
light having a single wavelength or frequency.
Invisible long frequencies of light beyond violet in the visible spectrum.
invisible short frequencies of light before red in the visible spectrum.
An atom or molecule bearing a positive or negative charge.
An image that cannot be seen directly. It can be seen only by a viewer looking through a lens.
An image formed by the actual convergence of light rays ona screen.
The lower lens of a microscopre which is positioned directly over speciments.
The lens of a microscope into which the viewer looks; same as an occular lense.
light that passes up from the condenser and through the speciment.
Illumination of a specimen from above; in microscopy it is used to examen opaque specimens.
The lens system under the microscope that focuses light onto the specimen.
Describes a microscope with only one eyepiece, lens.
Describes a microscope such that when an image is focused with one objective in position the other objective can be rotated into place.
Describes a microscope with two eyepieces.
Field of View
The area of the specimen that can be seen after it is magnified.
Depth of Focus
The thickness of a specimen that is entirely in focus under a microscope.
Plane Polarized Light
Light confined to a single plane of vibration.
A device that permits the passage of light waves vibrating in only one plane.
An instrument that links a microscope to a spectrophotometer.
Conditional use of a drug caused by underlying emotional needs.
Physiological need for a drug that has been brought about by its regular use. Dependence is characterized by withdrawls sickness when administration of the drug is abruptly stopped.
A substance that induces changed in mood, attitude, thought process, and perceptions.
A substance that depresses the functions of the central nervous system, depressants calm irritability and anxiety and may induce sleep.
A substance taken to increase alertness or activity.
Steroids that promote muscle growth.
A test that is nonspecific and preliminary in nature.
A single test that specifically identifies a substance in the body.
Tests to identify specific substances by the color and morphology of the crystals formed when the substance is mixed with specific reagent.
Passage of alcohol across the wall of the stomach and stomach and small intestine into the bloodstream.
The combination of oxygen with other substances to produce new products.
Elimination of alcohol from the body in an unchanged state; alcohol is normally excreted in breath and urine.
A blood vessel that carries blood away from the heart.
A blood vessel that transports blood towards the heart.
A tiny blood vessel across whoce walls exchange of materials between the blood and the tissues take place; recieves blood from arteries.
Small sacs in the lungs through whose walls air and other vapors are exchanged between breath and the blood.
Fuel Cell Detector
A detector in which chemical reactions produce eletricity.
A substance that prevent coagulation or clotthing of the blood.
A substance that stops the growth of microorganisms in blood.
To transform a chemical in the body to another chemical to facilitate its elimination from the body.
A compound capable of donating a hydrogen ion to another compound.
A compound capable of accepting a hydrogen ion
A scale used to express the basicity or acidity of a substance; pH neutral 7, 1-7 acid. 7 + Base.
A rod like structure in the cell nucleus, along which the genes are located, composed of DNA.
A substance composed of a large number of atoms; these atoms are usually arranged in repeating monomers.
The unit of DNA consisting of one of four bases Adenine, Guanine, Cytosinge, Thymine, they are phosphate sugar groups.
Complementary Base Pairing
The DNA helix strands have matching pairs of phosphate sugar groups. A+T C+G
polymers of amino acids that play basic roles in the structures and functions of living things.
The building blocks of proteins; there are twenty common amino acids.
The total DNA content found withi the nucleus of a human cell; three billion base pairs.
The synthesis of new DNA from existing DNA.
Polymerase Chain Reaction
A technique for replication or copying a portion of DNA strands outside a living cell.
A short strand of DNA used to target a regio of DNA for replication by PCR.
The process of joining two complementary strands of DNA to form a double stranded molecule.
A region of a chromosome that contains multiple copies of a core DNA sequence that are arranged in repeating fashion.
Restriction Fragment Length Polymorphism
Different fragment length of base pairs that result from cutting a DNA molecule with restriction enzymes.
Short Tandem Repeat
A region of a DNA molecule that contains short segments consisting of three to seven repeating base pairs.
A technique that simultaneously detects more than one DNA marker in a single analysis
A genetic locus useful for determing gender.
Short tandem repeats located on the human y chromosome.
Small structures loated outside the nucleus of a cell, powerhouse.
A procedure used to determine the order of the base pairs that constitute DNA.
Low Copy Number
Fewer than eighteen DNA bearing cells
One trillionth of a gram
The outher layer of skin cells, these DNA bearing cells often fall off of or are rubbed off onto objects retrieved from crime scenes.
DNA from skin cells transferred onto the surface of an object by simple contact.
Crime Scene Reconstruction
Method used to support a likely sequence of events at a crime scene by observation ect.
Small droplets of blood that are distributed around the perimeter of a drop or drops of blood and were produced as a result of the blood impacting the target surface.
Angle of Impact
The acute angle formed between the path of a blood drop and the surface that it contacts.
A bloodstain pattern produced when an object makes forceful contact with a source of blood, projecting drops of blood outward from the source.
Blood that travels away from the source in the same direction as the force that caused it.
blood directed back toward the source of the force that caused the spatter.
Low Velocity Spatter
An impact spatter pattern caused by a force traveling at five feet per second or less and producing drops with diameters greater than 3 mm.
Medium Velocity Spatter
An impact spatter pattern created by a force traveling at five to twenty five feet per second.
High Velocity Spatter
An impact spatter pattern created by a forc traveling at 100 feet per second or faster and producing drops less than 1 mm.
Area of Convergence
The area on a two dimensional plane where lines traced through the long axis of several individual bloodstains meet.
Area of Origin
The location in three dimensional space that blood that produced a bloodstain originated. Impact and angle are used to determine the origin.
A bloodstain pattern that is created when blood is flung from a blood bearing object into motion onto a surface.
A characteristic bloodstain pattern containing spurts that resulted from blood exiting under pressure from an arterial joint.
Expirated Blood Pattern
A pattern created by blood that i expelled out of the nose, mouth, or respitory system as a result of air pressure/flow
An area within a deposited spatter pattern that is clear of spatter, caused by an object or person blocking the area at the time of the splatter.
A bloodstain pattern created when a surface that carries wet blood comes in contact with a second surface.
A bloodstain pattern formed by the movement of small or large amonts of blood as a result of gravitys pull.
The process by which the edges of a stain dry to the surface in a specific perid of time on enviormental and surface.
Drip Trail Pattern
A pattern of bloodstains formed by the dripping of blood off a moving surface or person in a recognizable pathway, it's different from other patterns.
The scale structure covering the exterior of the hair.
The main body of the hair shaft.
A cellular column running through the center of the hair.
The initial growth phase during which the hair follicle actively produces hair.
A transition stage between the anagen and telogen phases of hair growth.
The final growth phase in which hair naturally falls out of the skin.
A translucent piece of tissue surrounding the hairs shaft near the root it contains the richest source of DNA associated with hair.
DNA present within the nucleus of a cell this form of DNA is inherited from both parents.
Inherited maternally from mom.
Fibers derived entirely from animal or plant sources.
Fibers derived from either natural or synthetic polymers the fibers are typically made by forcing material through a spinneret.
A substance composed of a large number of atoms these atoms are usuallly arranged in repeating units of monomers.
Two or more atoms held together by bonds.
A chemical or mechanical action caused by combustion, accompanied bycreation of heat and rapid expansion of gases.
A substance that supplies oxygen to a chemical reaction.
A very rapid oxidation reaction accompanied by the generation of a low intensity pressure wave that can disrupt the surroundings.
An extremely rapid oxidation reaction accompanied by a violent disruptive effect and an intense, high speed shock wave.
An explosive with a velocity of detonation less than one thousand meteres per second.
Normally a mixture of potassium nitrate, carbon, and sulfur.
A cord containing a core of black powder, used to carry a flame at a uniform rate to an explosive charge.
Single Base Smokeless Powder
An explosive consisting of nitrocellulos
Double Base Smokeless Powder
An explosive consisting of nitrocellulose and nitriglycerin.
An explosive with a velocity of detonation greater than one thousand meters per second.
A high explosive that is earily detonated by heat, shock or friction.
A high explosive that is relatively insensitive to heat, shock, or friction.
A cord like explosive containing a core of high explosive material usually PETN.
A verbal description of a perpetrators physical charachteristics and dress provided by a witness.
A system of identification of individuals by measurement of parts of the body, created by Alphonse Bertillon
Ridge endings, bifurications, enclosures, and other ridge details, which must match two fingerprints for a common origin to be established.
A fingerprint made by the deposit of oils and or perspiration, invisible to the naked eye.
A class of fingerprints characterized by ridge lines that enter from one side of the pattern and curve around the exit from the same side of the pattern.
A class of fingerprints that includes ridge patterns or circular in shape and have two deltas.
A class of fingerprints characterized by ridge lines that enter the print from one side and flow to the other.
An inkless device that captures the digital images of fingeprints and palm prints electronically transmits the images to AFIS.
A fingerprint made when the finger deposits a visible material such as ink/dirt/blood. ect.
A fingerprint impressed in a soft surface like a leather sofa.
The cut or low lying portions between the lands in a rifled bore.
The spiral grooves formed in the bore of a firearm barrel that impart spin to the projectile when fired.
The interior of a firearm barrel.
The raised portion between the grooves in a rifled bore.
The diameter of the bore of a rifled firearm in mm ex. wahlter p 22.
Size designation of a shotgun originally the number of lead bullets in a shell.
The mechanism in a firearm by which a cartridge of a fired case is withdrawn from the chamber.
The mechanism in a firearm that throws the cartridge or fired case from the firearm.
An interior constriction placed at or near the muzzle end of a shotguns barrel to control shot dispersion.
A chemical test used to develop patterns of gun powder residue around bullet holes.