Define identification and corpus delicti. Describe its medicolegal importance and the data used for identification.

Definition and Types

• Complete (absolute) identification — the absolute fixation of individuality, established beyond doubt by fingerprints, dental records or DNA
• Partial (incomplete) identification — only some data are ascertainable, so the field is narrowed but the individual is not fixed — a skeleton established to be that of a male aged 25 to 30 of about 170 cm
• Corpus delicti — literally "the body of the offence". It is not merely the dead body, which is the commonest misunderstanding. It means the essential facts showing that a crime has been committed — in homicide, the identity of the deceased and the fact that death was caused by a criminal act. Other components include the weapon, the bloodstains, the confession and the circumstantial evidence
• Conviction is possible without the body, where the corpus delicti is otherwise established by compelling circumstantial evidence — and Indian courts have so held. The rule exists because a murderer who successfully destroys or conceals a body would otherwise be immune

Medicolegal Importance

Data of Identification

• The value of each item differs enormously, and this is the point of the list: fingerprints, dental records and DNA can establish identity conclusively; scars, tattoos, moles and occupation marks are corroborative; and clothing, ornaments and personal effects are the weakest of all, because they are transferable and are the first thing an assailant changes
• Identification by relatives is notoriously unreliable in decomposition, burns and disaster, where distress and expectation produce confident errors in both directions — families have identified bodies that were not their relative and rejected bodies that were

Identification of the Living

• The general features — name and parentage, age, sex, religion, occupation, height, weight, complexion, hair and eye colour, and any deformity
• Two identification marks are recorded in every medicolegal examination — conventionally scars or moles, described with their exact position measured from a fixed bony landmark
• Occupation marks are of real value in an unknown person — callosities and stains of a characteristic distribution: the "tailor's notch" on the incisors of one who bites thread; callosities on the palms of a manual labourer; blue-black tattooing of coal dust in a miner's skin; discoloured fingers in a smoker or a chemical worker; a shoemaker's thumb; and the characteristic postures and deformities of long occupation
• Speech, gait, mannerisms and handwriting may be distinctive, and handwriting comparison is a recognised expert field
• Test identification parade — conducted by a magistrate, with the suspect placed among persons of similar appearance; the doctor may be asked about the witness's capacity to see and to remember

Reliability of the Different Data

Applied Aspects

• Record two identification marks in every medicolegal case, living or dead, with measurements from fixed landmarks; this is a routine requirement and its omission is noticed in court
• Do not rely on clothing and ornaments; they are the least reliable data and have produced serious errors, particularly in disasters where bodies are moved and possessions become separated
• Treat identification by a distressed relative with caution, and corroborate it with objective data wherever possible; a wrong identification means the wrong body is cremated and the right one is never found
• Preserve everything that could identify — the jaws and teeth, the hands for fingerprints, tissue for DNA, and any prosthesis or implant with its serial number, which can be traced to the manufacturer and thence to the recipient
• Corpus delicti does not require the body, and a doctor asked whether identification is possible should distinguish between what can be established conclusively, what is corroborative, and what is merely consistent
• Identification is the first step in every medicolegal autopsy; the doctor records who identified the body and how, since the entire subsequent report depends on that body being the one the case concerns
• Occupation marks are undervalued — a tailor’s notch, a coal miner’s tattooing or a labourer’s callosities can narrow an unknown body to a trade within minutes
• Photograph everything in colour with a scale, including scars, tattoos and deformities; descriptions are lost and photographs are not
• Complete identification requires a primary method — fingerprints, dentition, DNA or antemortem radiographs; everything else builds a profile that narrows the search
• Say which grade of evidence you are relying on; a report that mixes conclusive and corroborative findings without distinguishing them overstates its own certainty
• Corpus delicti requires the crime and the victim, not the body, and convictions have followed where the body was never recovered
• Ask what antemortem material exists at the outset — dental records, radiographs, fingerprints from employment or Aadhaar, and family DNA; identification is a matching exercise and needs both halves
• The identifying constable and the relative are recorded by name in the autopsy report; the doctor does not establish identity but must document who did
• Personal effects are the weakest evidence of all and the first thing an assailant alters; a body identified by its clothing has not been identified
• Religious and community markers narrow a search fast in India — circumcision, a sacred thread, a kara, ear-piercing and tattooed deities are often more useful than any anthropological measurement