Guide to Forensic Pathology

Jay Dix, Robert Calaluce

• Publisher: CRC Press
• Year: 2017
• ISBN:
  9781351443654
• Edition: 1
• Topic: Diritto
• Subtopic: Scienza forense

Guide to Forensic Pathology provides a concise overview of forensic pathology to those who wish to know the basics but lack formal forensic training. Both fascinating and practical, this book explains everything from who the experts are in death investigation and what their roles are to how effective testimonies are presented in court. The importance of forensic DNA testing is emphasized with a separate section in this timely reference guide.

PART I

Introduction

History

Death investigation in the United States originated in England. As early as the 12th century, there was an elected coroner who protected the crown’s interest from corrupt sheriffs. With time, the coroner’s jurisdiction over financial matters gave way to investigating deaths. The power of these death investigators grew to the degree that they could arrest suspected criminals and the sheriff (in Missouri the coroner can still arrest the sheriff). The coroner was required to assemble a group of Peers to judge a supsect’s guilt or innocence. This functioned as an early form of the inquest, a proceeding still conducted in some jurisdictions. The group also considered the necessity of a postmortem examination (autopsy).

The word autopsy is derived from ancient Greek and literally means to view for oneself.¹ Its common usage, however, is the postmortem examination of a body, including both an external viewing and an internal dissection, to determine the cause of death and a description of any pathological changes. In ancient cultures this examination is also associated with philosophical and religious issues such as one’s search and identification of the soul and understanding one’s own mortality. Consequently, it is not known when the first autopsy was performed. King and Mechan provide a good review of the history of the autopsy.²

The original settlers brought this system to our country and it remained similar to the English system for many years. The first person called a medical examiner was appointed in Boston during the late 1870’s. Neither the coroner nor the medical examiner had to be a forensic pathologist. The first citywide independent system for death investigation was established in New York City in 1918 and the first statewide system was developed in Maryland in 1939. There have been many changes throughout the country in death investigation during the ensuing decades.

Death investigation in the United States is performed differently from state to state and, in several states, from county to county. Some states have a statewide medical examiner system with trained forensic professionals. Other states retain the system of elected lay coroners who have little forensic or medical training. Except in a few states such as Missouri, in which medical examiners may be any type of physician, most medical examiners are forensic pathologists (see section about experts encountered in death investigation).

References:

1. Dorland’s Illustrated Medical Dictionary, 28th Ed. Philadelphia, W.B. Saunders Co., 1994.

2. King L., Mechan M.: A History of Autopsy: A Review. American Journal of Pathology 73: 514-544, 1973.

Experts Encountered In Death Investigation

Forensic Pathologist

Forensic pathology, a subspecialty in pathology, is the study of how and why people die. A physician who becomes a forensic pathologist first attends an approved pathology residency program and may spend three years in a strictly anatomic program or five years in a combined anatomic and clinical program. One or two additional years are devoted to studying the pathology of sudden, unexpected, natural death, as well as violent death, in one of approximately 30 approved forensic fellowship training programs throughout the country. Most programs are centered in major cities which have a large number of deaths from various causes. A forensic fellow studies how people die by: performing numerous autopsies; attending scene investigations; and studying the specialties of criminalistics, ballistics, serology, toxicology, anthropology, odontology, and radiology. The most important area of study is death investigation, but some forensic pathology programs also include examination of the living to determine physical and sexual abuse. After training, the pathologist is eligible to take a board certification examination in forensic pathology administered by the American Board of Pathology. There are fewer than 1,000 board certified forensic pathologists in the United States.

One definition of the word “forensic” means dealing with the courts and legal system. This definition describes two important functions of a forensic pathologist: deciding how and why a person died, and defending and explaining these diagnoses in a courtroom. A forensic pathologist may be called as a witness by either the prosecution or the defense. The state, however, usually calls a pathologist since he performed the autopsy. Regardless of who calls a pathologist to testify, the testimony should be an unbiased account of opinions as to why a person died or was injured. Medical information must be presented to a jury as clearly as possible since they will decide whether an accused person is guilty or innocent. A forensic pathologist must be an expert in death investigation. The importance of an investigation. in any death cannot be overemphasized. A scene investigation is probably more important than an autopsy. A thorough and complete investigation commonly leads an examiner to suspect the proper cause and manner of death prior to an autopsy. In many cases an autopsy is the only means to confirm what is already known and to collect specimens. Well-trained investigators are an integral part in any forensic jurisdiction. The importance of investigation will become more evident throughout the text.

Most full-time forensic pathologists work in either a medical examiner’s or coroner’s office located in larger cities. These offices may operate as separate departments or divisions of other city, county, or state agencies. For example, many are under the Attorney General’s Office or Departments of Health or Public Safety. These offices vary in jurisdiction in each state and usually investigate traumatic, sudden, unexpected, or suspicious deaths. They are also directly or indirectly connected to crime labs which have experts in serology, trace evidence, toxicology, and ballistics.

Medical Examiner or Coroner

The central character in medicolegal death investigation is the medical examiner or coroner. This person gathers information concerning the scene and autopsy in order to rule on both the cause and manner of death. A medical examiner or coroner may not perform the autopsy. In such cases, a pathologist’s findings are combined with the investigation to render a final opinion. Larger jurisdictions have their own investigators while smaller ones either rely on the local law enforcement agency or perform their own investigations.

Death Investigator

Larger jurisdictions may have their own investigators who receive an initial call to go to a death scene and make an evaluation. They report to a medical examiner or pathologist performing the autopsy. Their job is important because they work closely with law enforcement at a scene and obtain all necessary information about a decedent. They gather relevant medical history as well as talk to witnesses and relatives about a decedent’s last whereabouts and circumstances surrounding his death. This information is significant in determining the cause and manner of death because using autopsy information alone may lead to an inaccurate conclusion.

Crime Scene Technician

The crime scene technician’s job begins after a body discovered. This expert is specially trained and usually member of local law enforcement or a state-wide investigate unit. The technician’s expertise includes: photographing and diagramming the death scene; collecting all potentially important evidence in an investigation, such as blood, hair, fiber samples and weapons; and recovering fingerprints and other prints, such as those from shoes and tires.

Criminalist

This is the expert most people consider when evidence is sent to a forensic laboratory for analysis. The criminalist receives training in such areas as questioned documents, ballistics, serology, and toxicology. Most criminalists work with evidence (e.g., blood, bullets, fingerprints, ammunition) and trace evidence (e.g., fibers and hair, soil, glass, and impressions) left by other objects.

A ballistics expert can match a bullet from the victim to a test-fired weapon. This is accomplished by analyzing both a recovered bullet and a test-fired bullet under a comparison microscope. Every handgun and rifle has spiral grooves (lands-and-grooves) in the barrel which gives a bullet better trajectory. All weapons of similar type and manufacturer have the same number of lands-and-grooves. Therefore, an examiner can tell the type and make of gun which fired a bullet if it is not completely deformed. If a bullet has a metal jacket, such as copper, it will leave impressions from grooves that would not be seen on lead. The base of the cartridge can be examined for the firing pin impression which can also be matched to a particular gun. Shotgun pellets cannot be matched to a particular gun because there are no grooves in a shotgun barrel. The pellets are weighed for determination of size, and the lead composition is determined and compared to an unfired specimen.

A ballistics expert also performs tests for the presence of gunpowder residue on a suspect or the decedent. Such testing is helpful in determining if a person fired a weapon or was close to one when it was discharged. The tests will be of little value if the hands are not tested within approximately six hours of the firing, or if the alleged assailant washes his hands prior to the test.

This expert can test a variety of other materials such as soil for its component elements and glass for its fragility and direction of impact. Impressions, such as from a shoe sole or tire tread, can be matched to referenced products. Paint chips can be analyzed for their components and compared to the paint used by known manufacturers. Manufacturers of automobiles, for instance, keep accurate records of the paint used on each make and model. Volatile liquids, such as gasoline or paint thinner, can be determined from a suspected arson case.

Serologist

A serologist analyzes fluids such as blood, urine, or semen removed from a scene. If a specimen is not decomposed it can be compared to the blood types of all parties involved in an investigation. Blood need not be fluid to be of value; dried specimens, removed from weapons or other objects, are also useful. Occasionally, specific typing cannot be performed and a serologist can only determine whether or not such blood was human. DNA fingerprinting has also become very helpful. Everyone has unique DNA except identical twins. White blood cells can be examined for their DNA content and compared to other specimens. If a test uses strict scientific methodology, the results can be extremely valuable. DNA testing is also performed on hair, semen, and saliva.

A serologist can test semen for the presence and motility of sperm. Sperm remain motile for up to 24 hours before they die. Vaginal, oral, and anal swabs can also be tested for the presence of seminal fluid and sperm.

Secretors are people who secrete their blood type in their body fluids. Approximately 80% of all individuals are secretors. Blood, urine, sweat, saliva, and semen contain an individual’s blood type. Most people are type O, followed in order of decreasing frequency by A, B, and AB.

Questioned Documents Examiner

This person is able to analyze handwriting. He can determine whether or not a suspect actually wrote the document in question. Paper can be evaluated for its ingredients and age, and ink can be analyzed for its chemical composition. Writing

instruments such as typewriters or pens can also be evaluated.

Toxicologist

A toxicologist evaluates organs and fluids from an autopsy and a scene for the presence or absence of drugs and chemicals. The types of pills or powders found on suspects can also be determined. Most common drugs of abuse and poisons can be readily discovered and quantitated. Every drug and chemical, however, does not appear in a routine drug screen. A pathologist and investigator must consult with a toxicologist if any unusual drugs or poisons are suspected. They should also tell a toxicologist which prescribed or illegal drugs a decedent had taken. Drugs and medicines from a scene should be recovered for analysis if needed.

A report is produced after testing is completed. Generally, a toxicologist should refrain from giving an opinion as to the cause and manner of death because he is not aware of all information from an investigation and autopsy. It is a pathologist’s job to gather all the data and arrive at an explanation of a victim’s death.

Anthropologist

Anthropologists study bones and determine race, gender, and age range in most cases. Complete skeletons are easier to work with and yield more accurate results than partial skeletons. Some anthropologists specialize in reconstructing facial detail from skull bones and identifying unknown skeletons. Anthropologists, however, should not make a positive identification from bones alone unless other material is available for comparison, such as an x-ray or a detailed medical report. Anthropologists have been known to evaluate specific bony injuries in order to help with determining a cause of death.

Odontologist (Dentist)

A bite mark on a victim or an assailant can be matched to the person making the bite. An expert who can analyze and interpret this data undergoes specialized training. Prior to making molds and photographs of the marks, an odontologist swabs the area to remove any saliva. The blood type of an offender can be determined if the offender is a secretor. An odontologist is also an important consultant when positive identification is required. Only fingerprints are more commonly used than dental comparisons in identifying unknown bodies when visual identification cannot be made and a body is still intact.

Radiologist

A radiologist’s expertise is used frequently by a medical examiner’s office. Comparisons of antemortem to postmortem radiographs often aid in decedent identification. These analyses are very important when a decedent cannot be identified by fingerprints or dental exams. A radiologist is also consulted for evaluating bony abnormalities in cases of suspected child abuse.

Entomologist

Entomologists identify the type of insects at a scene and the age of larvae. They know which insects are prevalent at any particular time of the yea...