Unit 1 (history and introduction)

→ What are fingerprints?

Fingerprint are the reproduction of pattern of friction ridges present on distal phalanges of fingers and thumbs.

History of fingerprints

1. 221 BC - 220 AD

   • Chinese are 1st culture known to use friction ridge impressions as a means of identification

2. 1684

   • Friction ridge skin is first described in detail by Nehemiah Grew

3. 1697

   • Marcello Malphigi discovered basal layer generates cells, 1st to use microscope to study skin

4. 1788

   • J.C.A Mayer 1st to write that friction ridge skin is unique

5. 1856 - 1897

   • Hermann Welcker 1st person to start a permanence study

   • Sir William James Herschel 1st person to study persistence of friction ridge skin

6. 1858

   • Herschel’s spontaneous printing of man’s hand as proof of identity is first official use of friction ridge skin as a signature by a European

7. 1880

   • Henry Faulds 1st to publish in a scientific journal the value of friction ridge skin for individualisation.

8. 1883

   • Arthur Kollman 1st to identify presence and location of volar pads on the hands and feet

9. 1891

   • Juan Vucetich classification system and individualisation of prisoners through the use of fingerprints, 1st practical use of fingerprints by law enforcement personnel.

10. 1892

    • Rojas murder case [Argentina] 1st homicide solved by fingerprint evidence.

    • Sir Francis Galton authored 1st book on fingerprints

11. 1895

    • David Hepburn 1st to recognise friction ridge assist with grasping

12. 1894-97

    • Harris Hawthorn Wilder suggested the centres of disturbance of primate friction ridge formation representing the location of volar pads

13. 1897

    • Sir Edward Richard Henry first proposed workable classification system on fingerprints in India.

    • Two Bengali officers Khan Bahadur Azizul Haque, Rai Bahadur Hemchandra Bose of the anthropometric bureau played a very important role in the development of fingerprint classification system by assisting Henry.

14. 1898

    • 1st criminal case in bengal in which fingerprint evidence was used to secure a conviction.

15. 1900

    • Belper Committee recommended that all criminal investigation records be classified by Henry classification system

    • Sir Edward Richard Henry published his textbook “uses and classification of fingerprints” in 1900 when he was head of the metropolitan police force in London.

16. 1902

    • Alphonse Bertillon 1st to solve murder case in Europe using only fingerprint evidence

17. 1901

    • The Henry system of classification displaced the anthropometric system of Bertillon which was till then in use.

    • The fingerprint bureau was thus established at the Scotland yard .

18. 1907

    • Merry Holland 1st American female instructor of fingerprints

Fundamentals principles of fingerprints

• Individuality

  • 2 fingerprints cannot be the same. The characteristic features of a fingerprint are so unique that they are not exactly repeated in any other fingerprint or part of a fingerprint. These features enable personal identification with the help of fingerprints.

• Infallibility

  • Fingerprints are now universally recognised as an infallible means of personal identification as well as valuable aid to investigating officers in the detection and prosecution of crime and identification of criminals.

• Durability

  • almost everyone is born with fingers and fingers without exception have ridges. A fingerprint will remain unchanged throughout the life of an individual. Even if the external skin is damaged due to some reason, the ridges will reappear when the damage is repaired.

• Simplicity

  • although the scope for classification of fingerprints is large, it is so simple that can be done by any police personnel with little training. Records of millions of persons can be kept and retrieved easily with the help of a computer.

Significance of fingerprints

Fingerprints are one of the most valuable types of physical evidence in forensic science because they are unique, permanent, and can be used to identify individuals with high accuracy.

• uniqueness → every individual has a distinct fingerprint pattern even identical twins.

  • no two fingerprint are exactly the same in ridge detail, which makes them highly reliable for personal identification.

• permanence → fingerprint patterns are formed before birth ( around 10th week of fetal development) and remain unchanged throughout life.

  • even injuries like cuts or burns heal with the same ridge pattern, unless there is severe damage to the dermal layer.

• ease of collection → fingerprints can be collected relatively easily using powders, chemicals, or digital scanners.

  • they can be lifted from a variety of surfaces such as glass, metal, plastic or paper, making them practical in crime investigations.

• persistence → fingerprints remain on surfaces for long period under favourable conditions.

  • latent prints can often be recovered weeks or even months after being left behind, depending on the environment

• individualisation → fingerprints allow forensic experts to narrow down evidence to a single.

  • this helps in distinguishing one individual from all others with scientific certainty.

• legal admissibility → fingerprint evidence is widely accepted in courts as a reliable proof of identity.

  • its scientific basis and long history of use make it a trusted forensic method.

• linking suspect to the crime scene → prints found at a crime scene can connect a suspect to a specific location, object or victim

  • this helps investigators establish presence, contact or involvement in the crime.

Location

Fingerprints can be located in various areas connected to a crime scene. Common locations include →

• Crime scene → surfaces like tables, door, windows and floor where the perpetrator might have touched.

  • this helps reconstruct the sequence of events.

• Point of entry → doors, windows or other entry/exit points may hold prints showing how the suspects entered or left.

• vehicles → fingerprints may be found on car doors, steering wheels, gear levers, or mirrors if a vehicle was used in the crime.

• Objects belonging to the culprit → weapons, tools, mobile phones, or personal belonging handled by the suspect.

  • these can link the object directly to the individual

• Human bodies → fingerprints can sometimes be found on victim’s skin or belongings, especially in cases involving assault or physical contact.

Searching of fingerprints

1. Secure the scene → ensure the crime scene is protected from contamination.

   • limit entry to authorised personnel only to prevent accidental destruction of prints.

2. Preliminary survey → investigator visually examines the scene to identify areas most likely to have been touched.

   • focus is given to points of entry/exit, objects handled, and high contact surfaces.

3. Selection of search areas → priority is given to smooth, non-porous surfaces (glass, polished metal, plastic) where prints are easiest to detect.

   • porous surfaces (cardboard, paper) and semi porous (leather, wood) are also checked, but require special processing

4. Light and visual inspection → use of oblique lighting (light at a low angle) or flashlights to reveal latent prints.

   • Alternate light sources (ALS), such as UV or Blue light, help locate prints not visible to the naked eye

5. Physical methods of location → applying fingerprint powders (black, white, fluorescent) to reveal prints on non-porous surfaces.

   • magnetic powders are used for delicate or textured surfaces to prevent damage.

6. Chemical methods of location

   • Ninhydrin → for porous materials like paper, reacts with amino acids in sweat to produce a purple colour

   • cyanoacrylate fuming (superglue method) → for non porous surfaces, vapours bind to print residues and make them visible.

   • silver nitrate → reacts with chlorides in sweat, producing dark prints after exposure to light.

7. Use of optical enhancement → high resolution cameras and fingerprint scanners help detect faint impressions.

   • alters can be applied to enhance contrast in photographs

8. search patterns → investigators use systematic methods like grid method, strip search, or zone search to ensure no area is missed.

   • each section is processed before moving to the next one to maintain order.

9. Documentation before lifting → all visible or developed prints are photographed in situ (at the scene) before any attempt is made to lift them.

   • this preserves their appearance for court presentation

10. Lifting the fingerprints → adhesive lifting tape or gel lifters are used for powdered prints.

    • for developed prints on small objects, the entire object maybe collected as evidence

11. Marking and packaging → collected prints and photographs are labeled with date, time, location and collector’s name.

    • proper packaging prevents smudging or contamination

12. Chain of custody maintenance → all fingerprint evidence is documented and logged to maintain legal admissibility in court.