Latent Print Processing Guide

Stephen P. Kasper

• Publisher: Academic Press
• Year: 2015
• ISBN:
  9780128035436
• Topic: Law
• Subtopic: Forensic Science
• Index: Law

Latent prints are chance or accidental impressions left by friction-ridge skin on a surface, regardless of whether they are visible or invisible at the time of deposition. Recognition of evidence that may contain fingerprints and the processes that can develop these latent prints is crucial in preventing valuable evidence from being left undetected. Latent Print Processing Guide goes beyond the basic police training, covering latent prints in detail and providing first responders with adequate training and guidelines. To process latent prints, examiners use various techniques including electronic, chemical, cyanoacrylate, and physical methods. Latent Print Processing Guide offers a broad understanding of latent print detection, development, and recovery, including insights on stateof-the-art technologies.

• Includes history of latent print identification and some of the pioneers and their contributions. Defines the differences between chemical and physical processes and explains process sequence protocols and recovery methods for different types of evidence.
• Chapters include: process selection, application and recovery, special considerations for specific materials, protocol sequence and process formulas, including required materials, application method, expected results, safety measures, and references.
• The text is written so that non-crime scene or non-crime laboratory personnel can also gain valuable information from it.

Chapter 1

The Forensic Science of Fingerprints

Abstract

Chapter 1 is an introduction to the science and theory behind using fingerprints as a means of identification. An abridged history—from the earliest observation that fingerprint patterns were unique to when fingerprints were first allowed in court to identify suspects—is provided.

It also contains a section on basic definitions used in identifying the areas of the body containing friction ridge skin and details used to classify pattern types. The three basic fingerprint patterns are listed, as well as the three types of fingerprints: latent, patent, and plastic.

The basis of why fingerprints are used as positive identification is explained; the physical steps in an individual leaving a fingerprint, as well as the detection, development, and recovery of latent prints are also discussed.

An outline of the fingerprint identification process is explained, and a description of the Automated Fingerprint Identification System (AFIS) is offered.

Keywords

AFIS; Basis for use; Contaminant; Core; Definitions-Palmer; Delta; Fingerprint patterns; History; Identification process; Inked; Introduction; Latent; Matrix; Nonporous; Patent; Permanent; Plantar; Porous; Unique

Chapter Outline

Fingerprints 1

Brief History 1

Definitions 2

Types of Fingerprints 3

Why Fingerprints Are Used for Identification 4

How Fingerprints Are Produced 4

Detection and Development 4

Recovery and Preservation 5

Fingerprint Identification 5

AFIS (Automated Fingerprint Identification System) 6

Fingerprints

Fingerprints are the most dynamic form of evidence in existence… They are unique, permanent, objective and exact… The results are absolute and final.

Fingerprints can be identified to the exclusion of all others, which is not possible by other forms of forensic testing. Even DNA is not as exact, where identical twins have the same DNA.

Robert Hazen, Director of the FBI Latent Fingerprint Section, 1986

The “Science of Fingerprint Identification” begins at the point where material known as a matrix is transferred from an area of friction ridge skin to an object or surface. The “Science” continues on to detection, development, and recovery of the latent print, then to comparison with existing exemplars. The comparison process proceeds until a match or no match conclusion is reached and, ideally, culminates in individualization.

Brief History

For over 2000 years, humankind has known the value of fingerprints as a form of personalization. Chinese craftsmen during the “Tang” Dynasty signed their work with a thumb impression.

Early scientific notices of friction ridge peculiarities include the following:

Dr Nehemiah Grew was the first European to publish friction ridge skin observations. Dutch anatomist Govard Bidloo’s 1685 book, “Anatomy of the Human Body,” also described friction ridge skin (papillary ridge) details.

Marcello Malpighi noted fingerprint ridges, spirals, and loops in his treatise.

John Evangelist Purkinje published his thesis discussing nine fingerprint patterns.

No mention of friction ridge skin uniqueness, permanence, or the value of fingerprints for personal identification was made by Grew, Bidloo, Malpighi, or Purkinje.

The first recorded reference to the modern use of fingerprints as a means of identification appeared in 1788 when J.C.A. Mayer wrote, “Although the arrangement of skin ridges is never duplicated in two persons, never the less the similarities are clearer among some individuals. In others the differences are marked, yet in spite of their peculiarities of arrangement all have certain likeness.”

The actual use of fingerprints as a means of identification can be traced to India, where in 1858, Sir William James Herschel, a British official in India, began requiring a thumbprint of his subjects when they received goods and supplies. Although initially used as a ruse to prevent fraudulent double-dipping, he noticed that even though fingerprint patterns were similar, a close examination revealed minute differences allowing for individualization.

Other significant dates concerning the evolution of fingerprint identification:

• 1880—Dr Henry Faulds—devised methods for the taking of inked fingerprints that are still in use today.

• 1892—Sir Francis Galton—defined the five ridge detail types, now referred to as the Galton details.

• 1892—Juan Vucetich—the first recorded use of fingerprints for criminal identification (Argentina).

• 1901—Sir Edward Richard Henry—developed the Henry System of classification, a very intricate method for filing fingerprints so they may be located by means other than a subject’s name.

• 1904—Fingerprints are officially introduced in the United States at the World’s Fair in Saint Louis.

• 1911—Jennings versus Illinois—the first time fingerprints are allowed to be admitted as evidence in the US.

• 1924—The FBI Identification Division was formed.

Definitions

• Friction Ridge Skin—the portion of skin containing peaks and valleys, arranged in a pattern and located on the palmer and plantar surfaces.

• Palmer Surface—the palm side of hands, including fingers.

• Plantar Surface—the bottom of feet and toes.

• Latent Fingerprint—the word latent means to lie hidden or to escape notice. As it refers to crime scenes, latents are fingerprints that are involuntary recordings of the friction ridge skin scarcely or not visible, but they can be developed for study.

• Inked Fingerprint—an inked fingerprint is produced when a thin film of black printer ink is applied to the tops of the ridges present on the last finger joint, after which the finger is pressed against a white card or piece of paper. This effect creates a “stamp” of the fingerprint pattern.

• Core—a core is present in the Loop and Whorl patterns. It is essentially the center of the fingerprint pattern. It can be identified by the innermost recurving ridge in the Loop pattern and the center of the circular pattern in the Whorl.

• Delta—deltas are also present in Loop and Whorl patterns and are formed between the type lines (ridges) that flow in on one side and out on the other at the bottom and the ridges that recurve to encompass the center of the pattern. Their shape is similar to a river delta.

Fingerprint Patterns—fingerprint patterns, or ridge formations, are grouped in three categories, which are then broken down into eight subcategories: Arch, Tented arch, Right and Left slanted Loop, Whorl, Central pocket whorl, Double loop whorl, and Accidental whorl.

The three basic pattern forms are the following:

Arch—an Arch pattern is identified by the ridges flowing in on one side, forming a gentle “arch,” and flowing out on the other side.

Loop—the Loop can be distinguished by the formation of a ridge “loop” when at least one ridge flows in from one side, recurves, and exits out the same side it entered. The Loop also must have one delta.

Whorl—the Whorl is very distinct, as the ridges flow or tend to flow in a circular pattern. A whorl pattern contains two deltas.

Types of Fingerprints

The million dollar question… What types of surfaces can you get fingerprints off of?

The answer is pretty much everything: hard surfaces, soft surfaces, porous surfaces (paper), cloth, rock, even human skin. The key here is that a fingerprint is an imprint (reproduction) of a finger or a portion of friction ridge skin and is produced ...