ETC ETC Fingerprint & Biometric Evidence 3

Question 1

What type of fingerprint is formed when a finger presses into a soft material such as wax or putty, leaving a three-dimensional impression?

Accepted Answer

Plastic (impression) print

Answer

Plastic prints are three-dimensional impressions left in pliable materials like wax, putty, or fresh paint that retain the ridge detail in a molded form.

Question 2

When photographing a developed latent fingerprint, what must always be included in the frame?

Accepted Answer

A scale ruler placed adjacent to the print

Answer

A scale ruler (scale bar) must be photographed adjacent to the print so that images can be enlarged to 1:1 scale for accurate comparison.

Question 3

What is the delta in a fingerprint pattern?

Accepted Answer

A triangular ridge formation that marks a divergence of ridges, used as a reference point in classification

Answer

A delta is a triangular area where ridges diverge, serving as a key reference point for fingerprint classification; loops have one delta and whorls have two.

Question 4

Which chemical method uses the ninhydrin reaction to develop latent prints on paper documents in a dry environment?

Accepted Answer

Ninhydrin dip or spray followed by gentle heat application

Answer

Ninhydrin is applied by dipping or spraying on porous surfaces, then gently heated to accelerate the reaction with amino acids, producing a purple (Ruhemann's purple) color.

Question 5

Evidence technicians may be asked to obtain inked fingerprints from a deceased person. Which technique is used when skin is wrinkled or decomposed?

Accepted Answer

Tissue builder injection or rehydration using softening solutions prior to inking

Answer

Wrinkled or decomposed skin is treated with tissue builder injections or rehydration solutions to restore skin elasticity before inking, enabling legible prints.

(ETC) Evidence Technician Certification Practice Test

(ETC) Evidence Technician Certification Practice Test

ETC ETC Fingerprint & Biometric Evidence 3