Forensic science

# Overview
Forensic science (often shortened to forensics) is the application of a broad spectrum of sciences to answer questions of interest to the legal system. This may be in relation to a crime or to a civil action. But besides its relevance to the underlying legal system, more generally forensics encompasses the accepted scholarly or scientific methodology and norms under which the facts regarding an event, or an artifact, or some other physical item (such as a corpse, or cadaver, for example) are to the broader notion of authentication whereby an interest outside of a legal form exists in determining whether an object is in fact what it purports to be, or is alleged as being.
The word forensic comes from the Latin adjective forensis meaning of or before the forum. During the time of the Romans, a criminal charge meant presenting the case before a group of public individuals in the forum. Both the person accused of the crime and the accuser would give speeches based on their side of the story. The individual with the best argument and delivery would determine the outcome of the case. Basically, the person with the sharpest forensic skills would win.  This origin is the source of the two modern usages of the word "forensic" - as a form of legal evidence and as a category of public presentation.
In modern use, the term "forensics" in place of "forensic science" can be considered incorrect as the term "forensic" is effectively a synonym for "legal" or "related to courts". However, the term is now so closely associated with the scientific field that many dictionaries include the meaning that equates the word "forensics" with "forensic science".

# History of forensic science
The "Eureka" legend of Archimedes (287-212 BC) can be considered an early account of the use of forensic science. In this case, he determined that a crown was not completely made of gold (as it was fraudulently claimed) by determining its density by measuring its displacement and weight, as he was not allowed to damage the crown.
The earliest account of fingerprint use to establish identity was during the 7th century. According to an Arabic merchant, Soleiman,  a debtor's fingerprints were affixed to a bill, which would then be given to the lender. This bill was legally recognized as proof of the validity of the debt.
The first written account of using medicine and entomology to solve (separate) criminal cases is attributed to the book Xi Yuan Ji Lu (, translated as "Collected Cases of Injustice Rectified"), written in Song Dynasty China by Song Ci (, 1186-1249) in 1247. In one of the accounts, the case of a person murdered with a sickle was solved by a death investigator who instructed everyone to bring his sickle to one location.  Flies, attracted by the smell of blood, eventually gathered on a single sickle. In light of this, the murderer confessed. The book also offered advice on how to distinguish between a drowning (water in the lungs) and strangulation (broken neck cartilage), along with other evidence from examining corpses on determining if a death was caused by murder, suicide, or an accident.
In sixteenth century Europe, medical practitioners in army and university settings began to gather information on cause and manner of death. Ambroise Pare, a French army surgeon, systematically studied the effects of violent death on internal organs. Two Italian surgeons, Fortunato Fidelis and Paolo Zacchia, laid the foundation of modern pathology by studying changes which occurred in the structure of the body as the result of disease. In the late 1700s, writings on these topics began to appear. These included: "A Treatise on Forensic Medicine and Public Health" by the French physician Fodere, and "The Complete System of Police Medicine" by the German medical expert Johann Peter Franck.
In 1775, Swedish chemist Carl Wilhelm Scheele devised a way of detecting arsenous oxide, simple arsenic, in corpses, although only in large quantities. This investigation was expanded, in 1806, by German chemist Valentin Ross, who learned to detect the poison in the walls of a victim's stomach, and by English chemist James Marsh, who used chemical processes to confirm arsenic as the cause of death in an 1836 murder trial.
Two early examples of English forensic science in individual legal proceedings demonstrate the increasing use of logic and procedure in criminal investigations. In 1784, in Lancaster, England, John Toms was tried and convicted for murdering Edward Culshaw with a pistol. When the dead body of Culshaw was examined, a pistol wad (crushed paper used to secure powder and balls in the muzzle) found in his head wound matched perfectly with a torn newspaper found in Toms' pocket. In Warwick, England, in 1816, a farm labourer was tried and convicted of the murder of a young maidservant. She had been drowned in a shallow pool and bore the marks of violent assault. The police found footprints and an impression from corduroy cloth with a sewn patch in the damp earth near the pool. There were also scattered grains of wheat and chaff. The breeches of a farm labourer who had been threshing wheat nearby were examined and corresponded exactly to the impression in the earth near the pool. Later in the 20th century, several British pathologists, Bernard Spilsbury, Francis Camps, Sydney Smith and Keith Simpson would pioneer new forensic methods in Britain.

# Subdivisions of forensic science
- Criminalistics is the application of various sciences to answer questions relating to examination and comparison of biological evidence, trace evidence, impression evidence (such as fingerprints, footwear impressions, and tire tracks), controlled substances, ballistics (firearm examination), and other evidence in criminal investigations. Typically, evidence is processed in a crime lab.
- Digital forensics is the application of proven scientific methods and techniques in order to recover data from electronic / digital media.  DF specialist work in the field as well as in the lab.
- Forensic anthropology is the application of physical anthropology in a legal setting, usually for the recovery and identification of skeletonized human remains.
- Forensic archaeology is the application of a combination of archaeological techniques and forensic science, typically in law enforcement.
- Forensic entomology deals with the examination of insects in, on, and around human remains to assist in determination of time or location of death. It is also possible to determine if the body was moved after death.
- Forensic geology deals with trace evidence in the form of soils, minerals and petroleums.
- Forensic Interviewing is a method of communicating designed to elicit information and evidence.
- Forensic meteorology is a site specific analysis of past weather conditions for a point of loss.
- Forensic odontology is the study of the uniqueness of dentition better known as the study of teeth.
- Forensic pathology is a field in which the principles of medicine and pathology are applied to determine a cause of death or injury in the context of a legal inquiry.
- Forensic psychology is the study of the mind of an individual, using forensic methods. Usually it determines the circumstances behind a criminal's behavior.
- Forensic toxicology is the study of the effect of drugs and poisons on/in the human body.
- Forensic Document Examination or Questioned Document Examination  is the discipline that answers questions about a disputed document using a variety of scientific processes and methods. Many examinations involve a comparison of the questioned document, or components of the document, to a set of known standards. The most common type of examination involves handwriting wherein the examiner tries to address concerns about potential authorship.

# Questionable forensic techniques
Some forensic techniques, believed to be scientifically sound at the time they were used, have turned out later to have much less scientific merit, or none.  Some such techniques include:
- Comparative bullet-lead analysis was used by the FBI for over four decades, starting with the John F. Kennedy assassination in 1963.  The theory was that each batch of ammunition possessed a chemical makeup so distinct that a bullet could be traced back to a particular batch, or even a specific box.  However, internal studies and an outside study by the National Academy of Sciences found that the technique was unreliable, and the FBI abandoned the test in 2005.
- Forensic dentistry has come under fire; in at least two cases, bite mark evidence has been used to convict people of murder who were later freed by DNA evidence. A 1999 study by a member of the American Board of Forensic Odontology found a 63 percent rate of false identifications.

# Litigation science
Litigation science describes analyses or data developed or produced expressly for use in a trial, versus those produced in the course of independent research. This distinction was made by the U.S. 9th Circuit Court of Appeals when evaluating the admissibility of experts.