Category Archives: Forensic Science

Trace Evidence: Hair

by Kathy Steck- Flynn

Edmond Locard was the founder of the Institute of Criminalistics at the University of Lyon in France. Locard believed that that when on person came in contact with another person or object a cross transfer of minute particles occurred. This theory became known as the “Locard Exchange Principle”. Locard believed that crimes could be solved by inspecting the “dust particles” carried to and from a scene. This science is known today as criminalistics and has led to the rise of the forensics laboratory (from Mount Royal College background notes FORE 4407 section 3: Unit 4) Francois Goron, head of the French Surete, seems to be one of the first modern investigators who tried to use hair to identify a killer. In his first case hairs found clutched in a dead woman’s hand could not be identified as human simply because there was no information on the subject.

The inability of the scientific community to distinguish between animal and human hair raised interest in the analysis of hair. In the years that followed researchers began to collect information about the structure of human and animal hair (Block, 1979). In 1899, several years after his original failure, in a case known as “L’affaire Gouffe” Francois Goron was able to establish that a murder victim’s hair had been dyed. Establishing this simple fact led to the identification of Gouffe’s body and subsequently to the arrest of his killers (Block 1979). Francios Goron had successfully used forensic hair examination to solve a crime. Continue reading

Interpretation, Collection and Preservation of Glass Fragments

By Kathy Steck-Flynn

A man is found dead in an abandoned house. Upon examination the medical examiner finds that the man was killed by a single gunshot to the head. Three local teens where observed near the house two days earlier. They are picked up and questioned by police. When pressured, the teens admit to having stolen one of the boys’ father’s guns. They had taken turns shooting at the windows of an abandoned house.

The teens admit that John shot the gun first, then Jay and last was Fred. At the scene the investigators find three bullet holes in a window. They analyze the angle of each bullet hole in relation to the victim and find that the bullet which passed through the far right side of the window pane is the one which fatally wounded the man. Continue reading

Ninhydrin Processing

By Pat A. Wertheim

This article originally appeared in Minutiae, the Lightning Powder Co. Newsletter, #45, November-December 1997.

Perhaps the most productive and cost-effective method of developing latent fingerprints on paper is treatment with Ninhydrin. Freshly-mixed Ninhydrin solutions are less expensive and more dependable than premixed aerosol cans or pump spray dispensers. While the premixed containers are ready for instant use when purchased, safety experts today caution against spraying and instead encourage either dipping or painting to apply the solution.

The problem with spraying Ninhydrin solutions is that, even in a fume hood, airborne particles of Ninhydrin dust can form as the carrier evaporates. These microscopic particles may not be effectively removed from the lab by the fume hood, and may find their way back into the air you breathe. Since Ninhydrin reacts with amino acids, any exposure to your body, especially to your eyes or lungs, could have serious results. This potentially dangerous exposure is minimized by dipping or painting. Continue reading

Atmospheric Superglue Method

By Pat A. Wertheim

This article originally appeared in Minutiae, the Lightning Powder Co. Newsletter, #44, Sep-Oct 1997.

Some latent print technicians believe superglue should be listed second only to powder as the most effective latent print development technique. Others believe it should come first. Either way, no one can deny that superglue fuming is the most revolutionary new method to be discovered since the invention of powder. Superglue fuming works on many surfaces where powder is ineffective, such as plastics, and has the advantage of fixing the print on the surface for later presentation in court. Continue reading

Footwear, the Missed Evidence

Dwayne S. Hilderbrand, CLPE
Lead Latent Print Examiner
Scottsdale Police Crime Lab

This article originally appeared in Minutiae, The Lightning Powder Co. Newsletter, Nov-Dec 1995, p. 2-5, 11.

“The scope of a complete examination consists of two main functions: first,
the recovery process, which includes the discovery and preservation of the
prints, and second, the identification process, which involves evaluations,
comparisons, and findings related to the recovered impression.”

(Grieve 1988).

Introduction

“Wherever he steps, whatever he touches, whatever he leaves, even
unconsciously, will serve as silent witness against him. Not only his
fingerprints or his footprints, but his hair, the fibers from his clothing,
the glass he breaks, the tool mark he leaves, the paint he scratches, the
blood or semen he deposits or collects.. All of these and more bear mute
witness against him. This is evidence that does not forget. It is not confused
by the excitement of the moment. It is not absent because human witnesses
are, it is factual evidence, physical evidence cannot be wrong, it cannot
perjure itself; it cannot be wholly absent, only its interpretation can err.
Only human failure to find it, study and understand it, can diminish its
value.”

(Paul L. Kirk 1974).

On September 19, 1991, two German tourists were hiking in the mountains on the border between Austria and Italy when they spotted a body buried in the ice. The two tourists, suspecting foul play, contacted the authorities. As it was not clear at the time exactly where the body was found, police authorities from Austria and Italy responded. Following the normal procedures for the recovery of the body, they attempted to free it from the ice using jack hammers. Unfortunately, the jack hammers were damaging the body, pickaxes and ski poles were then used.

Continue reading

Fingerprinting the Dead

by Daryl W. Clemens

Plastic Tape

Plastic Tape

Obtaining fingerprints for identification is a long established law enforcement practice. When the practice started, is was most common to use printers ink applied to the fingers which were then pressed onto paper cards. Later specialized inks were employed to improve the quality of the prints obtained. While ink is still used today, many agencies are now using computer “live-scan” methods to record reference prints. Continue reading

Ear Identification

Presented at the conference for Shoeprint and Toolmark Examiners Noordwijkerhout, 24 April 1997.

Introduction:
The subject of my presentation for this conference is ear research / ear identification. It concerns not only the research into the adversity of ears but also the finding of earprints especially in relation to committed penal acts. My further reasoning will be separated into four parts.

1. A piece of history according to ear research and what is known about that subject in literature.

2. The history of ear research in the Netherlands in which I will indicate the present state of affairs.

3. International developments (as far as I’m concerned).

4. The criminological value of earprints in the future, especially my views on the internationalization of earprint research, standard norms and co-operation. Continue reading

Latent Prints in Dust

by Captain Curtis C. Frame,
Criminal Investigation Division
Jasper County Sheriff’s Office
Jasper, Texas
Article Copyright © 2000, Curtis C. Frame

A Latent print found in dust, may be the only clue to a case in which there are no other leads. And because the areas that are routinely touched by the victims are not normally dusty, the dust print we find may be the only link we have of the perpetrator to the crime scene. However, most crime scene and latent print examiner experts will say that, regardless of their importance, latent prints in dust are a nightmare. This is due to the fact that a latent print in dust was actually left there due to the dust being removed by adhering to the ridges of the skin that touched it. Continue reading

Condom Trace Evidence: A New Factor in Sexual Assault Investigations

By Robert D. Blackledge, M.S.
Mr. Blackledge is senior chemist at the Naval Criminal Investigative Service Regional Forensic Laboratory in San Diego, California.

This Article Originally Appeared in the FBI Law Enforcement Bulletin, May 1996.

(Offenders are changing the nature of sexual assault investigations by wearing condoms.)
In an age filled with potentially fatal sexually transmitted diseases, more and more individuals practice safe sex. Even perpetrators of sex crimes have begun to wear condoms.1 It is not likely that a fear of disease prompts this behavior. Rather, just as a burglar dons gloves to avoid leaving fingerprints, sexual offenders now wear condoms to avoid depositing seminal fluids. Continue reading

Black Powder Processing

By Pat A. Wertheim

This article originally appeared in “Minutiae”, The Lightning Powder Co. Newsletter, No. 42, May-June 1997, p. 6.

Although old-fashioned black powder is the workhorse of fingerprint development
techniques for crime scene use and is also an important method in the laboratory,
maximizing the effectiveness of powder requires far more sophistication than
simply dipping a brush into the jar of powder and painting it onto a surface.

More control can be exercised over black powder by working out of a shallow
dish. The perfect disposable dish can be made by cutting or tearing a blank
inked fingerprint card from any edge into the center of the card. Overlap
the two edges of the cut by about an inch (two or three centimeters) and
tape the card back together to make the dish. A large laboratory weighing
dish may be used, or any other shallow dish or bowl. Place one-half to one
teaspoon of powder (approximately one millilitre) into the dish. Continue reading