Magnetic Powder

By Pat A. Wertheim

This article originally appeared in Minutiae, the Lightning Powder Co. Newsletter, #43, July-August 1997.

Even though magnetic powder has been available since the early 1960’s, many latent print examiners and crime scene technicians are still not using it to full advantage. Magnetic powder adds a wide range of flexibility to one’s resources. In general, magnetic powder is used on non-magnetic surfaces, and regular powder on iron-based surfaces. However, regular fingerprint powder is inappropriate for some surfaces, including many plastics and textured surfaces, where magnetic powder develops latent prints very well. Textured surfaces such as vinyl imitation-leather or lightly textured automobile dashboards or door panels often respond well to magnetic powder, where regular powder would pack into the low places in the texturing and make development of a good latent impossible. In addition, using the “hot breath” technique, also known as “huffing” works better with magnetic powder than with regular powder. Continue reading

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

Statement Analysis: What Do Suspects’ Words Really Reveal?

By Susan H. Adams, M.A.
Special Agent Adams teaches statement analysis as part of interviewing and interrogation courses at the FBI Academy.

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

(In statement analysis, investigators examine words, independent of case facts, to detect deception.)

Susan Smith stood outside her burgundy sedan and released the parking brake. The car plunged down the ramp into South Carolina’s Long Lake, with her sons, Michael, 3, and Alexander, 14 months, strapped into their car seats. To cover her actions, Susan told police that the boys were abducted at gunpoint, launching a nationwide search for the victims and their abductor. During the investigation, Susan tearfully told reporters, “My children wanted me. They needed me. And now I can’t help them.”1

Yet, the boys’ father, David, who believed Susan’s story, tried to reassure her by saying: “They’re okay. They’re going to be home soon.”2

Police subsequently arrested Susan for the murder of her children. She was tried and convicted and is currently serving a life sentence in a South Carolina correctional institution. Many investigators use a technique called “statement analysis” to discern the truth in statements like the ones given by Susan and David Smith. In statement analysis, investigators examine words, independent of case facts, to detect deception. They also remain alert for information omitted and question why the suspect may have done so. Investigators then analyze the clues unintentionally provided by a suspect and use this insight during the subsequent interview. 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

The Forensic Antropologist

By
Robert W. Mann, M.A.
and
Douglas H. Ubelaker, Ph.D.
Physical Anthropologists Department of Anthropology Smithsonian Institution, Washington, D.C.

This Article Originally Appeared in the FBI Law Enforcement Bulletin, July 1990.

In recent years, just as the investigation of a crime scene has become more complex and sophisticated, so has the task of the forensic anthropologist. Forensic anthropologists assist medical and legal specialists to identify known or suspected human remains.

The science of forensic anthropology includes archeological excavation; examination of hair, insects, plant materials and footprints; determination of elapsed time since death; facial reproduction; photographic superimposition; detection of anatomical variants; and analysis of past injury and medical treatment. However, in practice, forensic anthropologists primarily help to identify a decedent based on the available evidence. Continue reading

Intent Behind the Bullet

by D.H. Garrison, Jr.

Originally published in the Association of Firearm Toolmark Examiners Journal, Oct. 1993.

Just because a shot was fired, and just because someone was injured or died as a result of the shooting, and just because a shooting reconstruction was completed…this does not mean that the expert can render an opinion about the intent behind the bullet thus fired.

While many an attorney, whether prosecution or defense, wants to “prove” the intent or lack thereof to a jury, and sometimes tries to use a expert witness to accomplish that end, this does not mean that the shooting reconstruction expert has any scientific basis whatsoever to state an opinion as to what was or was not the intention of the shooter at the moment of the shooting. Intent, after all, is usually an “ultimate issue” and, thus, the purview of the jury, the finders of fact, and cannot properly be addressed by the expert.[1] Continue reading

An Introduction to Crime Scene Reconstruction for the Criminal Profiler

by Daryl W. Clemens

This article originally appeared in the MAFS newsletter, 27(2), April 1998.

Definitions:

Crime Scene Reconstruction- The use of scientific methods, physical evidence, deductive reasoning and their interrelationships to gain explicit knowledge of the series of events that surround the commission of a crime.
-Association for Crime Scene Reconstruction, The Scene, 4(1), Jan 1997, p. 2.

Criminal Profiling- The application of psychological theory to the analysis and reconstruction of the forensic evidence that relates to an offender’s crime scenes, victims and behaviors.
– Turvey, B., “CP101: An Introduction to Criminal Profiling”, Online Course,
http://www.corpus-delicti.com, May 1997.
Introduction

While both of these activities may appear to be similar and are in fact related, it is important to note that they are not the same. The difference between the two is most easily understood by looking at which questions about the crime they attempt to answer.1,2,3,4 Crime Scene Reconstruction looks at the physical evidence and attempts to determine “What happened?” and “How did it happen?”.5,6 Criminal Profiling looks at the physical evidence and the reconstruction and attempts to determine “Why may this have happened?” and “What does that tell us about Who may have done it?”.7 It is important to keep in mind that only those directly involved in the crime know for sure what happened and why, and they may be unable or unwilling to say. 8,9

Continue reading

Why Crime Scene Reconstruction Does Not Answer the Why? Question

By Dean H. Garrison, Jr.

This article originally appeared in the MAFS newsletter April 1996.

“I tend not to try to determine why people do things at crime scenes.”
-Criminalist Charles Morton
California v Menedez II, Trial transcript 12-5-95

Crime scene reconstruction may answer the question of where a victim was standing when an axe hit him or who stepped in the pool of blood by the door or what caused the revolver’s hammer to fall or when the third shot hit the car window or how the knife ended up out on the patio, but the crime scene reconstructionist cannot answer the ultimate question, the final question that tugs at everyone’s mind, the all-encompassing, all-seeing, all-knowing question of WHY did the crime happen? This may account for the fact that attorneys (for either side) very seldom ask “Why?” questions. Continue reading