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Forensic identification is the application of forensic science, or "forensics", and technology to identify specific objects from the trace evidence they leave, often at a crime scene or the scene of an accident. Forensic means "for the courts".


Human identification

People can be identified by their
fingerprint A fingerprint is an impression left by the friction ridges of a human finger. The recovery of partial fingerprints from a crime scene is an important method of forensic science. Moisture and grease on a finger result in fingerprints on surfac ...
s. This assertion is supported by the philosophy of
friction ridge The dermis or corium is a layer of skin between the epidermis (with which it makes up the cutis) and subcutaneous tissues, that primarily consists of dense irregular connective tissue and cushions the body from stress and strain. It is divided ...
identification, which states that friction ridge identification is established through the agreement of friction ridge formations, in sequence, having sufficient uniqueness to individualize. Friction ridge identification is also governed by four premises or statements of facts: # Friction ridges develop on the fetus in their definitive form prior to birth. # Friction ridges are persistent throughout life except for permanent scarring, disease, or decomposition after death. # Friction ridge paths and the details in small areas of friction ridges are unique and never repeated. # Overall, friction ridge patterns vary within limits which allow for classification. People can also be identified from traces of their DNA from blood, skin, hair, saliva, and semen by
DNA fingerprinting DNA profiling (also called DNA fingerprinting) is the process of determining an individual's DNA characteristics. DNA analysis intended to identify a species, rather than an individual, is called DNA barcoding. DNA profiling is a forensic t ...
, from their ear print, from their teeth or bite by forensic odontology, from a photograph or a video recording by facial recognition systems, from the video recording of their walk by gait analysis, from an audio recording by
voice analysis Voice analysis is the study of speech sounds for purposes other than linguistic content, such as in speech recognition. Such studies include mostly medical analysis of the voice (phoniatrics), but also speaker identification. More controversiall ...
, from their handwriting by handwriting analysis, from the content of their writings by their writing style (e.g. typical phrases, factual bias, and/or misspellings of words), or from other traces using other biometric techniques. Many methods that are used in forensic science evidence have been proven to be unreliable. A lot of trials have been reviewed and testimony involving mostly microscopic hair comparison, but also bite mark, shoe print, soil, fiber, and fingerprint comparisons have been overturned because forensic analysts have provided invalid testimony at the trial. Since forensic identification has been first introduced to the courts in 1980, the first exoneration due to DNA evidence was in 1989 and there have been 336 additional exonerations since then. Those who specialize in forensic identification continue to make headway with new discoveries and technological advances to make convictions more accurate.
Body identification Body identification is a subfield of forensic science that uses a variety of scientific and non-scientific methods to identify a body. Forensic purposes are served by rigorous scientific forensic identification techniques, but these are generall ...
is a subfield of forensics concerned with identifying someone from their remains, usually from fingerprint analysis, dental analysis, or DNA analysis.


Foot creases

Feet also have friction ridges like fingerprints do. Friction ridges have been widely accepted as a form of identification with fingerprints but not entirely with feet. Feet have creases which remain over time due to the depth it reaches in the dermal layer of the skin, making them permanent. These creases are valuable when individualizing the owner. The concept of no two fingerprints are alike is also applied to foot creases. Foot creases can grow as early as 13 weeks after conception when the volar pads begin to grow and when the pads regress, the creases remain. When foot crease identification is used in a criminal case, it should be used in conjunction with morphology and friction ridges to ensure precise identification. There is record of foot crease identification used in a criminal case to solve a murder. Sometimes with marks left by the foot with ink, blood, mud, or other substances, the appearance of creases or ridges become muddled or extra creases may appear due to cracked skin, folded skin, or fissures. In order to truly compare morphological feature, the prints of feet must be clear enough to distinguish between individuals.


Downfalls

The two basic conceptual foundations of forensic identification are that everyone is individualized and unique. This individualization belief was invented by a police records clerk,
Alphonse Bertillon Alphonse Bertillon (; 22 April 1853 – 13 February 1914) was a French police officer and biometrics researcher who applied the anthropological technique of anthropometry to law enforcement creating an identification system based on physical me ...
, based on the idea that "nature never repeats," originating from the father of social statistics, Lambert Adolphe Jacques Quetelet. The belief was passed down through generations being generally accepted, but it was never scientifically proven. There was a study done intending to show that no two fingerprints were the same, but the results were inconclusive. Many modern forensic and evidentiary scholars collectively agree that individualization to one object, such as a fingerprint, bite mark, handwriting, or ear mark is not possible. In court cases, forensic scientists can fall victim to
observer bias Observer bias is one of the types of detection bias and is defined as any kind of systematic divergence from accurate facts during observation and the recording of data and information in studies. The definition can be further expanded upon to inclu ...
when not sufficiently blinded to the case or results of other pertinent tests. This has happened in cases like
United States v. Green
' and
State v. Langill
'. Also, th
proficiency tests
that forensic analysts must do are often not as demanding to be considered admissible in court.


DNA identification

Forensic DNA analysis can be a useful tool in aiding forensic identification because DNA is found in almost all cells of our bodies except red blood cells. Deoxyribonucleic acid is located in two different places of the cell, the
nucleus Nucleus ( : nuclei) is a Latin word for the seed inside a fruit. It most often refers to: * Atomic nucleus, the very dense central region of an atom *Cell nucleus, a central organelle of a eukaryotic cell, containing most of the cell's DNA Nucl ...
; which is inherited from both parents, and the
mitochondria A mitochondrion (; ) is an organelle found in the cells of most Eukaryotes, such as animals, plants and fungi. Mitochondria have a double membrane structure and use aerobic respiration to generate adenosine triphosphate (ATP), which is used ...
; inherited maternally. As with fingerprints, an individual's DNA profile and characteristics are unique. Forensic identification using DNA can be useful in different cases such as determining suspects in violent crimes, solving paternity/maternity, and identifying human remains of victims from mass disasters or missing person cases. It is also used to link suspects or victims to each other or to crime scenes. When a sample is located at a crime scene, it must be collected, processed, and transported, along with a chain of custody, to the laboratory for analysis, so that if a DNA profile is generated it can be accepted in court. Proper evidence collection and preservation is crucial to ensure evidence is not being contaminated. Main procedures investigators must use when packaging biological material is allowing the evidence to air dry and then package into paper bags. Plastic bags should never be used on biological evidence because it could degrade DNA or lead to bacterial growth. DNA can be sourced from biological material such as semen, blood, saliva, feces, urine, teeth, bone, and hair that is left behind from an individual. There are different presumptive and confirmatory tests used for each type of biological material found at a scene. Presumptive tests are quick, sensitive and are relatively specific to bodily fluids that give the analyst an idea of what might be present. Confirmatory tests confirm what the biological sample is. In addition to looking for biological material at a crime scene, pieces of evidence can also be examined and analyzed for the presence of DNA. Evidence pieces that may have the presence of DNA could include clothing, bedding, weapons, masks, gloves, among many others. This is attributed to touch DNA, where only minute samples are left after an object has been touched. It is defined as “evidence with no visible staining that would likely contain DNA resulting from the transfer of epithelial cells from the skin to an object.” A forensic scientist can attempt to obtain a DNA profile from the sample with as few as six cells. The first step in the DNA process with a piece of evidence is
extraction Extraction may refer to: Science and technology Biology and medicine * Comedo extraction, a method of acne treatment * Dental extraction, the surgical removal of a tooth from the mouth Computing and information science * Data extraction, the pr ...
. Extraction is a technique used to remove the DNA from the cell. The next step would be quantification which determines how much DNA is present. The third step is amplification in order to yield multiple copies of DNA. Next is separation, to separate the DNA out to use for identification. Finally, the analyst can now complete analysis and interpretation of the DNA sample and compare to known profiles. An unknown sample found at a crime scene is called a questioned sample. A known sample can be taken either from a suspect or found in a
database In computing, a database is an organized collection of data stored and accessed electronically. Small databases can be stored on a file system, while large databases are hosted on computer clusters or cloud storage. The design of databases ...
. The FBI’s database used for DNA is
CODIS The Combined DNA Index System (CODIS) is the United States national DNA database created and maintained by the Federal Bureau of Investigation. CODIS consists of three levels of information; Local DNA Index Systems (LDIS) where DNA profiles ori ...
, Combined DNA Index System. It has data at three levels: local, state, and national. The national level data is stored in NDIS, National DNA Index system. CODIS/NDIS allows analysts to compare their questioned DNA profile among those of arrestees, convicted offenders, and other unknown samples to try and produce investigative leads. If questioned and known samples are similar,
statistics Statistics (from German: '' Statistik'', "description of a state, a country") is the discipline that concerns the collection, organization, analysis, interpretation, and presentation of data. In applying statistics to a scientific, indust ...
and interpretation will then be completed. The DNA profile will be compared to a population database and a random match probability will be determined. Random match probability is defined as the chance that an individual selected randomly from a population will have an identical DNA profile to the markers tested. If they do not equal each other, they are not a match, termed exclusion. During
DNA typing Genetic testing, also known as DNA testing, is used to identify changes in DNA sequence or chromosome structure. Genetic testing can also include measuring the results of genetic changes, such as RNA analysis as an output of gene expression, or ...
, several markers are examined, termed loci. When more markers are examined, this could result in either a greater probability that two unrelated individuals will have different genotypes or adds to the confidence of connecting an individual to an unknown sample. One locus difference between a questioned and known sample is enough to exclude that suspect as the contributor. The FBI has identified 13 core STR loci that are effective for human identification. STR is
short tandem repeats A microsatellite is a tract of repetitive DNA in which certain DNA motifs (ranging in length from one to six or more base pairs) are repeated, typically 5–50 times. Microsatellites occur at thousands of locations within an organism's genome. ...
which are short DNA regions in the
genome In the fields of molecular biology and genetics, a genome is all the genetic information of an organism. It consists of nucleotide sequences of DNA (or RNA in RNA viruses). The nuclear genome includes protein-coding genes and non-coding ...
and are 2-6 base pairs in length. STR is common in forensic analysis because they are easily amplified using
polymerase chain reaction The polymerase chain reaction (PCR) is a method widely used to rapidly make millions to billions of copies (complete or partial) of a specific DNA sample, allowing scientists to take a very small sample of DNA and amplify it (or a part of it) ...
(PCR) and they have unique variation among individuals for human identification. PCR is the technique of copying DNA by making millions of copies. When all 13 core loci are tested on a DNA profile, the random match probability is more than one in a trillion. Since DNA was first used in a criminal investigation in 1986, it has aided investigators to solve many cases. DNA profiling is one of the most important tools in forensics and continued research will increase its ability and accuracy to provide more techniques for the future.


Animal identification


Wildlife forensics

There are many different applications for wildlife forensics and below are only some of the procedures and processes used to distinguish species. Species identification: The importance of
species In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriat ...
identification is most prominent in animal populations that are illegally hunted, harvested, and traded, such as rhinoceroses, lions, and African elephants. In order to distinguish which species is which, mtDNA, or mitochondrial DNA, is the most used genetic marker because it is easier to type from highly decomposed and processed tissue compared to nuclear DNA. Additionally, the mitochondrial DNA has multiple copies per cell, which is another reason it's frequently used. When nuclear DNA is used, certain segments of the strands are amplified in order to compare those to segments of mitochondrial DNA. This comparison is used to figure out related genes and species proximity since distant relatives of animals are closer in proximity in the gene tree. That being said, the comparison process demands precision because mistakes can easily be made due to genes evolving and
mutating In biology, a mutation is an alteration in the nucleic acid sequence of the genome of an organism, virus, or extrachromosomal DNA. Viral genomes contain either DNA or RNA. Mutations result from errors during DNA or viral replication, mitosi ...
in the evolution of species. Determination of geographic origin: Determining the origin of a certain species aids research in population numbers and lineage data.
Phylogenetic In biology, phylogenetics (; from Greek φυλή/ φῦλον [] "tribe, clan, race", and wikt:γενετικός, γενετικός [] "origin, source, birth") is the study of the evolutionary history and relationships among or within groups ...
studies are most often used to find the broad geographic area of which a species reside. For example, in California seahorses were being sold for traditional medicinal purposes and the phylogenetic data of those seahorses led researchers to find their origin and from which population they came from and what species they were. In addition to phylogenetic data
assignment tests
are used to find the probability of a species belonging to or originating from a specific population and genetic markers of a specimen are utilized. These types of tests are most accurate when all potential population's data have been gathered. Statistical analyses are used in assignment tests based on an individual's
microsatellite A microsatellite is a tract of repetitive DNA in which certain DNA motifs (ranging in length from one to six or more base pairs) are repeated, typically 5–50 times. Microsatellites occur at thousands of locations within an organism's genome. ...
s or Amplified Fragment Length Polymorphisms (AFLPs). Using microsatellites in these studies is more favorable than AFLPs because the AFLPs required non-degraded tissue samples and higher errors have been reported when using AFLPs.


Domestic animal forensics

Domestic animals such as dogs and cats can be utilized to help solve criminal cases. These can include homicides, sexual assaults, or robberies. DNA evidence from dogs alone have helped over 20 criminal cases in Great Britain and the U.S. since 1996. However, there are very few laboratories that are able to process and analyze evidence or data from domestic animals. Forensics can be used in animal attacks as well. In cases such as dog attacks, the hair, blood, and saliva surrounding the wounds a victim has can be analyzed to find a match for the attacker. In the competitive realm, DNA analysis is used in many cases to find illegal substances in racehorses by urine samples and comparisons of STRs.


Product identification

* Color copiers and maybe some color
computer printer In computing, a printer is a peripheral machine which makes a persistent representation of graphics or text, usually on paper. While most output is human-readable, bar code printers are an example of an expanded use for printers. Diffe ...
s steganographically embed their identification number as a countermeasure against currency forgeries. * Copiers and
computer printer In computing, a printer is a peripheral machine which makes a persistent representation of graphics or text, usually on paper. While most output is human-readable, bar code printers are an example of an expanded use for printers. Diffe ...
s can be potentially identified by the minor variants of the way they feed the paper through the printing mechanism, leaving banding artifacts. Analysis of the
toner Toner is a powder mixture used in laser printers and photocopiers to form the printed text and images on paper, in general through a toner cartridge. Mostly granulated plastic, early mixtures only added carbon powder and iron oxide, however, ...
s is also used. *
Document A document is a written, drawn, presented, or memorialized representation of thought, often the manifestation of non-fictional, as well as fictional, content. The word originates from the Latin ''Documentum'', which denotes a "teaching" o ...
s are characterized by the composition of their
paper Paper is a thin sheet material produced by mechanically or chemically processing cellulose fibres derived from wood, rags, grasses or other vegetable sources in water, draining the water through fine mesh leaving the fibre evenly distribu ...
and ink. *
Firearm A firearm is any type of gun designed to be readily carried and used by an individual. The term is legally defined further in different countries (see Legal definitions). The first firearms originated in 10th-century China, when bamboo tubes ...
s can be identified by the striations on the bullets they fired and imprints on the cartridge casings. *
Paper shredder A paper shredder is a mechanical device used to cut sheets of paper into either strips or fine particles. Government organizations, businesses, and private individuals use shredders to destroy private, confidential, or otherwise sensitive docum ...
s can be potentially identified in a similar way, by spacing and wear of their blades. *
Photo identification Photo identification or photo ID is an identity document that includes a photograph of the holder, usually only their face. The most commonly accepted forms of photo ID are those issued by government authorities, such as driver's licenses, ide ...
is used to detect and identify forged digital photos. *
Typewriter A typewriter is a mechanical or electromechanical machine for typing characters. Typically, a typewriter has an array of keys, and each one causes a different single character to be produced on paper by striking an inked ribbon selectivel ...
s can be identified by minor variations of positioning and wear of their letters. * Illegal drugs can be identified by which color it turns when a reagent is added during a color test. Gas Chromatography, Infrared Spectrometry or Mass Spectrometry is used in combination with the color test to identify the type of drug.


Networks

* Cars can be automatically found on
CCTV Closed-circuit television (CCTV), also known as video surveillance, is the use of video cameras to transmit a signal to a specific place, on a limited set of monitors. It differs from broadcast television in that the signal is not openly ...
records by
automatic number plate recognition Automatic number-plate recognition (ANPR; see also other names below) is a technology that uses optical character recognition on images to read vehicle registration plates to create vehicle location data. It can use existing closed-circuit tel ...
. * Computers connected to the
Internet The Internet (or internet) is the global system of interconnected computer networks that uses the Internet protocol suite (TCP/IP) to communicate between networks and devices. It is a '' network of networks'' that consists of private, p ...
can often be identified by their
IP address An Internet Protocol address (IP address) is a numerical label such as that is connected to a computer network that uses the Internet Protocol for communication.. Updated by . An IP address serves two main functions: network interface ident ...
or
MAC address A media access control address (MAC address) is a unique identifier assigned to a network interface controller (NIC) for use as a network address in communications within a network segment. This use is common in most IEEE 802 networking te ...
. * Radio transceivers can be potentially identified by minute variations of their output signal. * Social networks can be discovered by
network analysis Network analysis can refer to: * Network theory, the analysis of relations through mathematical graphs ** Social network analysis, network theory applied to social relations * Network analysis (electrical circuits) See also *Network planning and d ...
of banking, telecommunication and postal records.


Applications

Sometimes,
manufacturer Manufacturing is the creation or production of goods with the help of equipment, labor, machines, tools, and chemical or biological processing or formulation. It is the essence of secondary sector of the economy. The term may refer to ...
s and
film distributor A film distributor is responsible for the marketing of a film. The distribution company may be the same with, or different from, the production company. Distribution deals are an important part of financing a film. The distributor may set the ...
s may intentionally leave subtle forensic markings on their products to identify them in case of piracy or involvement in a crime. (''Cf.''
watermark A watermark is an identifying image or pattern in paper that appears as various shades of lightness/darkness when viewed by transmitted light (or when viewed by reflected light, atop a dark background), caused by thickness or density variations ...
, digital watermark, steganography.
DNA marking DNA marking is a type of forensic identification. It is a method to mark items in a way that is undetectable to the naked eye. A unique DNA marker is applied to the item, and can be recovered to identify the item. In suspected thefts, the suspect ...
.)


Organizations

* Association of Firearm and Tool Mark Examiners *
Canadian Identification Society The Canadian Identification Society (CIS) is a bilingual (English- French) professional non-for-profit fellowship of police officers and civilian members who share interests and employment in crime scene investigation. Also known in French as (S ...
* International Association for Identification


See also

*
Biometric identification Biometrics are body measurements and calculations related to human characteristics. Biometric authentication (or realistic authentication) is used in computer science as a form of identification and access control. It is also used to identify in ...
*
Computer forensics Computer forensics (also known as computer forensic science) is a branch of digital forensic science pertaining to evidence found in computers and digital storage media. The goal of computer forensics is to examine digital media in a forensica ...
* Data remanence * Digital traces * Entomological evidence collection * Forensic anthropology * Forensic dentistry (odontology) * Forensic engineering * Forensic profiling * Forensic science * Identification (biology) * Mass surveillance *
Privacy Privacy (, ) is the ability of an individual or group to seclude themselves or information about themselves, and thereby express themselves selectively. The domain of privacy partially overlaps with security, which can include the concepts of ...
* Surveillance * Trace evidence *
Questioned Document Examination In forensic science, questioned document examination (QDE) is the examination of documents potentially disputed in a court of law. Its primary purpose is to provide evidence about a suspicious or questionable document using scientific processe ...


References


External links


bio-forensics.com
bioFORENSICS - Tools for forensic identification
Onin.com
Forensic Fingerprinting
Cis.sci.ca
Canadian Identification Society {{DEFAULTSORT:Forensic Identification Surveillance
Identification Identification or identify may refer to: *Identity document, any document used to verify a person's identity Arts, entertainment and media * ''Identify'' (album) by Got7, 2014 * "Identify" (song), by Natalie Imbruglia, 1999 * Identification ( ...