Crime Scene Investigation: Fingerprint Evidence

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Questions and Answers

What is the primary objective of this lesson plan?

To discuss the physical process by which fingerprints are formed
To practice locating, developing, and lifting latent fingerprints from various surfaces (correct)
To identify the equipment needed to record suspect and elimination fingerprints
To identify the basic evidentiary value of fingerprints found at a crime scene

What is the purpose of obtaining both suspect and elimination fingerprint impressions?

To differentiate between latent and patent fingerprints
To identify the quality of fingerprint impressions
To identify the reasons for obtaining both suspect and elimination fingerprint impressions is not provided in the text (correct)
To determine the pattern groups used to classify fingerprints

What is the purpose of rolling fingerprints on standard ten-print cards?

To practice locating latent fingerprints from various surfaces
To demonstrate the method used to retrieve fingerprints from various surfaces
To practice recording suspect and elimination fingerprints (correct)
To identify the three pattern groups used to classify fingerprints

What will the trainees be able to do after completing this lesson?

All of the above (D) Signup and view all the answers

What is the timeframe allocated for this lesson?

6 hours (B) Signup and view all the answers

When was this lesson plan prepared?

November 20, 2008 (C) Signup and view all the answers

What is the purpose of having the subject wash their hands before taking their fingerprints?

To remove perspiration and dirt (B) Signup and view all the answers

What should be the color of a good fingerprint impression?

Dark gray (A) Signup and view all the answers

Why should the subject's fingers be held straight and stiff during the plain impression process?

To ensure a level plane at the wrist (B) Signup and view all the answers

What can cause poorly prepared fingerprint records?

Too much ink used and unevenly distributed (B) Signup and view all the answers

Why might ridge characteristics be indistinct in some individuals?

Due to the subject's occupation (C) Signup and view all the answers

What should be done if a digit is missing during the recording process?

Mark the space for the missing digit (B) Signup and view all the answers

What is the primary composition of a fingerprint?

98% perspiration, 1% amino acids, and 1% oil (C) Signup and view all the answers

What is the most common type of fingerprint pattern found in the population?

Loops (A) Signup and view all the answers

What is the purpose of using a flashlight to locate fingerprints at a crime scene?

To shine light at a 45-degree angle to the surface (B) Signup and view all the answers

What is the name of the process used to detect oils in perspiration at a crime scene?

Iodine fuming (C) Signup and view all the answers

What is the primary difference between rolled and plain (PAT) fingerprint impressions?

Rolled impressions are used for identification, while plain impressions are used for elimination (C) Signup and view all the answers

What is the name of the system used to store and retrieve fingerprint cards for comparison?

Fingerprint classification system (D) Signup and view all the answers

What is the purpose of using a two-part system on the standard 10-print record card?

To record basic pedigree information and rolling of all 10 digits (A) Signup and view all the answers

What is the primary advantage of using printer's or commercial fingerprint ink?

It reduces smudging and maintains consistency (C) Signup and view all the answers

What is the purpose of using a glass plate in fingerprint recording equipment?

To hold the ink (B) Signup and view all the answers

What is the primary precaution to take when dusting for fingerprints at a crime scene?

Use a light movement of the brush (A) Signup and view all the answers

Study Notes

Fingerprint Evidence

Fingerprint is a deposit consisting of 98% perspiration, 1% amino acids, and 1% oil that forms on the friction ridges of fingers, palms, and feet, and is left on a surface when contact is made.

Factors Affecting Fingerprint Impression Quality

Condition of the hand: • Must be clean and dry • Age can affect the friction ridges • Occupation of subject can affect the friction ridges
Type of Surface: • Smooth, hard, clean surfaces are most likely to reveal prints • Rough, porous, dusty, dirty, or greasy surfaces are least likely to reveal fingerprint impressions • Atmospheric conditions

Fingerprint Classification

Fingerprints are classified into three pattern types and eight sub-groups: • Arches (5% of population) • Loops (60% of population) • Whorls (35% of population)

Fingerprint Impressions

There are three types of fingerprint impressions: • Patent (visible) • Latent (invisible) • Plastic (molded)

Fingerprint Recording Equipment and Process

Standard 10-Print Record Card: • Currently used by most law enforcement agencies • Allows recording of basic pedigree information and rolling of all 10 digits
Recording Process: • Preparation: clean hands, glass plate, ink, and roller • Rolling Impressions:
- Have subject sign 10-print card
- Roll four fingers away from center of subject's body
- Roll thumbs toward center of subject's body
- Apply steady/even downward pressure • Plain (PAT) Impressions:
- Have subject sign 10-print card
- Subject holds fingers together straight and stiff
- Finger printer holds wrist and presses fingers simultaneously on ink pad, then onto print card in appropriate box

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Description

This lesson plan covers the physical process of fingerprint formation, types of impressions and patterns, and methods to obtain fingerprint evidence. Trainees will practice rolling fingerprints on standard ten-print cards.