Latent Fingerprint Development

Latent Fingerprint Development Quiz crafted by :

Neeti Kapoor

Assistant Professor,

Dept. of Forensic Science

Government Institute of Forensic Science, Nagpur, India

Introduction to Latent prints

We touch things every day: a coffee cup, a car door, a computer keyboard. Each time we do, it is likely that we leave behind our unique signature—in our fingerprints.

Latent prints are impressions produced by the ridged skin, known as friction ridges, on human fingers, palms, and soles to the feet. They are prints left behind at the scene of crime. Such prints may or may not be visible to the naked eye. These prints are made of the sweat and oil present on the skin’s surface. These prints require additional processing such as basic powder techniques or the use of chemicals in order to be seen.

Importance of latent print in forensics: Fingerprint analysis has been used to identify suspects and solve crimes for more than 100 years, and it remains an extremely valuable tool for law enforcement. Examiners analyze and compare latent prints to known prints of individuals in an effort to make identifications or exclusions.

Future perspective: The  development of  new techniques and advancements  to image & visualize latent fingermarks for identification continues to simultaneously detect and obtain latent marks at crime scenes; a holy grail for forensic science.

Here is the List of Questions with Answers along with explanation

Ques 1. 1,8-Diazafluoren-9-one (DFO) has the maximum absorption range between

a. 520-560nm

b. 400-600nm

c. 240-300nm

d. 150-425nm

Answer- (a) 520-560nm

Explanation- Latent fingerprints that were treated with DFO displayed only a faint red color but they luminesced brightly under green light (absorption maximum at about 470 nm and emission maximum at about 570 nm). These properties very quickly made DFO the most important fluorogenic reagent for latent fingerprints.

Ques 2. Gardenia jasminoides react with amino acids and forms a ________ colored fingerprint.

a. Blue

b. Brown

c. Red orange

d. Purple

Answer- (a) Blue

Explanation- Genipin is an aglycone derived from geniposide, found in the fruit of gardenia jasminoides. Genipin itself is colorless but it reacts spontaneously with amino acids to form blue color print.

Ques 3. Who is the author of the thesis titled “Commentary on the Physiological Examination of the Organs of Vision and the Cutaneous System”?

a. Dr.  Henry Lee

b. Dr. Edward Richard Henry

c. Dr. Johannes E. Purkinje

d. Dr. William Herschel

Answer- (b) Dr. Johannes E. Purkinje

Explanation - Dr.Johannes Purkinje made notable achievements in dactloscopy. His 1823 thesis, Commentary on the Physiological Examination of the Organs of Vision and the Cutaneous System, contains a detailed description, complete with meticulous illustrations , of  9 principal fingerprint patterns, classified in Latin.

Ques 4. Physical developer (PD) technique cannot be used after using _______ reagent.

a. DFO

b. Silver Nitrate  

c. Oil red O

d. Ninhydrin

Answer- (b) Silver Nitrate  

Explanation- PD is used to develop latent prints on porous and certain non-porous surfaces. This process cannot be used in conjuction with silver nitrate method, however if used will negate the silver nitrate process .

Ques 5. Nile red interacts and fluoresce in the presence of compound/s like

a. Cholesterol

b. Phospholipids

c. Triglycerides

d. All the above 

Answer- (d) All the above 

Explanation- Nile red has been used to develop fingerprints on porous surfaces. Nile red targets the lipids found in sebaceous gland secretions and has been demonstrated to develop five year old uncharged marks. As all options A, B & C are types of lipids , hence option D is correct.

Ques 6. Europium Chelate used for developing fingerprints has the property of

a. High luminescence efficiency

b. Large Stokes shift

c. Long luminescence lifetime

d. All the above

Answer- (d) All the above

Explanation- Europium is being reported  in many recent advances in luminescence detection of fingerprints, as Eu is typically a member of lanthanide series it emits luminescene with large stokes shift, high luminescence efficiency and long lifetime luminescene also.

Ques 7. The dye stain RAY can develop prints on-

a. Adhesive side of tape

b. Non-adhesive side of the tape

c. Porous surface

d. Both b and c

Answer- (a) Adhesive side of tape

Explanation- RAY dye stain is a fluorescent mixture of Rhodamine, Ardrox, and Baisc Yellow. It is a new method used in processing the adhesive side of tape after it has been exposed to cyanoacrylate fumes.

Ques 8. Methyl Violet 10B produces good results on latent fingerprint development on surfaces like-

a. Polythene

b. Aluminum

c. Paper

d. Wood

Answer- (a) Polythene

Explanation- Methyl violet 10B also known as crystal violet. It is particularly efficient for detection of latent marks on adhesive surfaces such as pressure – sensitive tapes and films, therefore option A (polythene) is the right answer.

Ques  9. Which of the following enzyme(s)is/are used for both pre and post treatment of ninhydrin?

a. Trypsin

b. Pronase

c. Fumerase

d. Both a and b

Answer- (d) Both a and b

Explanation- Improving the enhancement of ninhydrin-developed fingerprints Everse and Menzel reported that there was a pronounced enhancement of the detectability of latent prints by combining pretreatment with trypsin or pronase with post treatment with zinc chloride followed by examination by argon laser light. 

Ques 10. The prints can be developed on the emulsion side of thermal paper because of the coating of-

a. Fluorenleuco dye

b. Azo dyes

c. Aniline dyes

d. Anthraquilone dyes

Answer- (a) Fluorenleuco dye

Explanation - The surface of thermal paper is coated with a solid –state mixture of dye and a suitable matrix; a combination of fluoranleuco dye. The prints develop due to the components in fingerprint that affect the solubility and hence changes color of the dye.

Ques 11. Sequence for developing prints on the emulsion side of thermal paper is-

a. HCl vapor, DFO, Dry Ninhydrin

b. Dry Ninhydrin, DFO, HCl vapor

c. DFO, HCl vapor, Dry Ninhydrin

d. Dry Ninhydrin, HCl vapor, DFO

Answer- (a) HCl vapor, DFO, Dry Ninhydrin

Explanation - To develop prints subsequent testing and standardized processes is to be conducted. The thermal paper is fumed by means of exposure to the muriatic acid vapour and then processed by DFO and ninhydrin in the respective order.So, option “a” has the right sequence.

Ques 12. __________ is a reddish protein stain used to enhance bloody friction ridge detail.

a. Coppersulphate

b. Fluoboric acid

c. Acid Fuschin

d. A-Naphaflavone

Answer-(a) Acid Fuschin

Explanation- Acid Fuchsin also known as Hungarian red is an excellent stain for the enhancement of bloody fingerprints .It is safer than some other methods due to its water based formula.

Ques 13. Which famous author was the first to utilise fingerprint evidence to solve a fictional crime?

a. Rudyard Kipling

b. Sherlock Holmes

c. Sir Arthur Conan Doyle

d. Agatha Christie

Answer- (c) Sir Arthur Conan Doyle

Explanation - Sherlock Holmes the very famous first fictional detective created by Sir Arthur Conan Doyle’s was quick to realize the value of fingerprint evidence. The first case in which fingerprints are mentioned is The Sign of Four, published in 1890.

Ques 14. Latent fingerprints deposited on silicon wafers can be developed using __________ under UV illumination.

a. AUNPs

b. CdSe/ZnS Quantum dots

c. AgNO3

d. Turmeric powder

Answer- (b) CdSe/ZnS Quantum dots

Explanation- Nanoparticles – and more specifically quantum dots (QDs) are raising new possibilities for latent fingerprint development with a high level of contrast, sensitivity, and selectivity .CdSe/ZnS QDs have been used for developing latent fingerprints as they luminescent under UV illumination.

Ques 15. Gun Blueing is a solution consisting of ___________, used to develop friction ridges.

a. Hallucal

b. Gold chloride, Glacial Acetic Acid, Gentian Violet

c. Acetic Acid, Selenious Acid and Cupric Salt

d. Hungarian red, Hydrogen Peroxide and Ethanol

Answer-  (c) Acetic Acid, Selenious Acid and Cupric Salt

Explanation -Gun blue is only capable of developing friction ridge details on the metal surfaces by certain chemical reactions. Gun blueing solution consists of three active ingredients : an acid, cupric salt ,and selenious acid.